Unable to send unauthenticated SMTP #460

New Issue

MrUnknownDE · 2026-04-05T21:22:03+02:00

MrUnknownDE commented

2026-04-05 21:22:03 +02:00

Originally created by @bm-brown on 7/22/2025

Prerequisites

I have searched the existing issues and discussions
I have read the documentation

Vaultwarden Support String

Your environment (Generated via diagnostics page)

Vaultwarden version: v1.34.1
Web-vault version: v2025.5.0
OS/Arch: linux/x86_64
Running within a container: true (Base: Debian)
Database type: SQLite
Database version: 3.49.1
Uses config.json: true
Uses a reverse proxy: true
IP Header check: true (X-Forwarded-For)
Internet access: true
Internet access via a proxy: false
DNS Check: true
TZ environment: America/New_York
Browser/Server Time Check: true
Server/NTP Time Check: true
Domain Configuration Check: true
HTTPS Check: true
Websocket Check: true
HTTP Response Checks: true

Config & Details (Generated via diagnostics page)

Show Config & Details

Environment settings which are overridden: SIGNUPS_ALLOWED, SMTP_HOST, SMTP_PORT, SMTP_FROM

Config:

{
  "_duo_akey": null,
  "_enable_duo": true,
  "_enable_email_2fa": true,
  "_enable_smtp": true,
  "_enable_yubico": true,
  "_icon_service_csp": "",
  "_icon_service_url": "",
  "_ip_header_enabled": true,
  "_max_note_size": 10000,
  "_smtp_img_src": "*****://****************************",
  "admin_ratelimit_max_burst": 3,
  "admin_ratelimit_seconds": 300,
  "admin_session_lifetime": 20,
  "admin_token": "***",
  "allowed_connect_src": "",
  "allowed_iframe_ancestors": "",
  "attachments_folder": "data/attachments",
  "auth_request_purge_schedule": "30 * * * * *",
  "authenticator_disable_time_drift": false,
  "data_folder": "data",
  "database_conn_init": "",
  "database_max_conns": 10,
  "database_timeout": 30,
  "database_url": "***************",
  "db_connection_retries": 15,
  "disable_2fa_remember": false,
  "disable_admin_token": false,
  "disable_icon_download": false,
  "domain": "*****://*****************",
  "domain_origin": "*****://*****************",
  "domain_path": "",
  "domain_set": true,
  "duo_context_purge_schedule": "30 * * * * *",
  "duo_host": null,
  "duo_ikey": null,
  "duo_skey": null,
  "duo_use_iframe": false,
  "email_2fa_auto_fallback": false,
  "email_2fa_enforce_on_verified_invite": false,
  "email_attempts_limit": 3,
  "email_change_allowed": true,
  "email_expiration_time": 600,
  "email_token_size": 6,
  "emergency_access_allowed": true,
  "emergency_notification_reminder_schedule": "0 3 * * * *",
  "emergency_request_timeout_schedule": "0 7 * * * *",
  "enable_db_wal": true,
  "enable_websocket": true,
  "enforce_single_org_with_reset_pw_policy": false,
  "event_cleanup_schedule": "0 10 0 * * *",
  "events_days_retain": null,
  "experimental_client_feature_flags": "",
  "extended_logging": true,
  "helo_name": null,
  "hibp_api_key": null,
  "http_request_block_non_global_ips": true,
  "http_request_block_regex": null,
  "icon_blacklist_non_global_ips": true,
  "icon_blacklist_regex": null,
  "icon_cache_folder": "data/icon_cache",
  "icon_cache_negttl": 259200,
  "icon_cache_ttl": 2592000,
  "icon_download_timeout": 10,
  "icon_redirect_code": 302,
  "icon_service": "internal",
  "incomplete_2fa_schedule": "30 * * * * *",
  "incomplete_2fa_time_limit": 3,
  "increase_note_size_limit": false,
  "invitation_expiration_hours": 120,
  "invitation_org_name": "Vaultwarden",
  "invitations_allowed": true,
  "ip_header": "X-Forwarded-For",
  "job_poll_interval_ms": 30000,
  "log_file": null,
  "log_level": "info",
  "log_timestamp_format": "%Y-%m-%d %H:%M:%S.%3f",
  "login_ratelimit_max_burst": 10,
  "login_ratelimit_seconds": 60,
  "org_attachment_limit": null,
  "org_creation_users": "",
  "org_events_enabled": false,
  "org_groups_enabled": false,
  "password_hints_allowed": true,
  "password_iterations": 600000,
  "push_enabled": false,
  "push_identity_uri": "https://identity.bitwarden.com",
  "push_installation_id": "***",
  "push_installation_key": "***",
  "push_relay_uri": "https://push.bitwarden.com",
  "reload_templates": false,
  "require_device_email": false,
  "rsa_key_filename": "data/rsa_key",
  "send_purge_schedule": "0 5 * * * *",
  "sendmail_command": null,
  "sends_allowed": true,
  "sends_folder": "data/sends",
  "show_password_hint": false,
  "signups_allowed": false,
  "signups_domains_whitelist": "",
  "signups_verify": false,
  "signups_verify_resend_limit": 6,
  "signups_verify_resend_time": 3600,
  "smtp_accept_invalid_certs": false,
  "smtp_accept_invalid_hostnames": false,
  "smtp_auth_mechanism": "",
  "smtp_debug": true,
  "smtp_embed_images": false,
  "smtp_explicit_tls": null,
  "smtp_from": "***********************",
  "smtp_from_name": "Vaultwarden",
  "smtp_host": "*********************",
  "smtp_password": "***",
  "smtp_port": 25,
  "smtp_security": "off",
  "smtp_ssl": null,
  "smtp_timeout": 15,
  "smtp_username": "",
  "templates_folder": "data/templates",
  "tmp_folder": "data/tmp",
  "trash_auto_delete_days": null,
  "trash_purge_schedule": "0 5 0 * * *",
  "use_sendmail": false,
  "use_syslog": false,
  "user_attachment_limit": null,
  "user_send_limit": null,
  "web_vault_enabled": true,
  "web_vault_folder": "web-vault/",
  "yubico_client_id": null,
  "yubico_secret_key": null,
  "yubico_server": null
}

Vaultwarden Build Version

1.34.1

Deployment method

Official Container Image

Custom deployment method

No response

Reverse Proxy

Apache/2.4.62

Host/Server Operating System

Linux

Operating System Version

AlmaLinux 9

Clients

Web Vault

Client Version

2025.5.0, multiple firefox and edge browsers

Steps To Reproduce

Configure SMTP with no authentication method (SMTP_AUTH_MECHANISM=off, blank, etc)
Attempt to send test SMTP or user invite
Receive error: "SMTP client error: internal client error: No compatible authentication mechanism was found"

Expected Result

SMTP Sent without error

Actual Result

SMTP client error: internal client error: No compatible authentication mechanism was found

Logs

[2025-07-22 10:28:46.972][request][INFO] POST /admin/invite
[2025-07-22 10:28:46.974][vaultwarden::mail][WARN] No valid SMTP Auth mechanism found for '', using default values
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 220 mailout3.sunyocc.edu ESMTP Postfix<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] Wrote: EHLO 7de164919099<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF>250-8BITMIME<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF>250-8BITMIME<CRLF>250 DSN<CRLF>
[2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] server mailout3.sunyocc.edu with {EightBitMime}
[2025-07-22 10:28:46.979][vaultwarden::mail][ERROR] SMTP client error: internal client error: No compatible authentication mechanism was found
[2025-07-22 10:28:46.980][response][INFO] (invite_user) POST /admin/invite application/json => 500 Internal Server Error

Screenshots or Videos

No response

Additional Context

I am able to telnet to the postfix relay server and send a 'EHLO test.mail' and confirm the responses do not include an auth request. I have others non-authenticated clients able to send SMTP to this relay as well.

I suspect not having any auth mechanism is failing a check for this function.

*Originally created by @bm-brown on 7/22/2025* ### Prerequisites - [x] I have searched the existing issues and discussions - [x] I have read the documentation ### Vaultwarden Support String ### Your environment (Generated via diagnostics page) * Vaultwarden version: v1.34.1 * Web-vault version: v2025.5.0 * OS/Arch: linux/x86_64 * Running within a container: true (Base: Debian) * Database type: SQLite * Database version: 3.49.1 * Uses config.json: true * Uses a reverse proxy: true * IP Header check: true (X-Forwarded-For) * Internet access: true * Internet access via a proxy: false * DNS Check: true * TZ environment: America/New_York * Browser/Server Time Check: true * Server/NTP Time Check: true * Domain Configuration Check: true * HTTPS Check: true * Websocket Check: true * HTTP Response Checks: true ### Config & Details (Generated via diagnostics page) <details><summary>Show Config & Details</summary> **Environment settings which are overridden:** SIGNUPS_ALLOWED, SMTP_HOST, SMTP_PORT, SMTP_FROM **Config:** ```json { "_duo_akey": null, "_enable_duo": true, "_enable_email_2fa": true, "_enable_smtp": true, "_enable_yubico": true, "_icon_service_csp": "", "_icon_service_url": "", "_ip_header_enabled": true, "_max_note_size": 10000, "_smtp_img_src": "*****://****************************", "admin_ratelimit_max_burst": 3, "admin_ratelimit_seconds": 300, "admin_session_lifetime": 20, "admin_token": "***", "allowed_connect_src": "", "allowed_iframe_ancestors": "", "attachments_folder": "data/attachments", "auth_request_purge_schedule": "30 * * * * *", "authenticator_disable_time_drift": false, "data_folder": "data", "database_conn_init": "", "database_max_conns": 10, "database_timeout": 30, "database_url": "***************", "db_connection_retries": 15, "disable_2fa_remember": false, "disable_admin_token": false, "disable_icon_download": false, "domain": "*****://*****************", "domain_origin": "*****://*****************", "domain_path": "", "domain_set": true, "duo_context_purge_schedule": "30 * * * * *", "duo_host": null, "duo_ikey": null, "duo_skey": null, "duo_use_iframe": false, "email_2fa_auto_fallback": false, "email_2fa_enforce_on_verified_invite": false, "email_attempts_limit": 3, "email_change_allowed": true, "email_expiration_time": 600, "email_token_size": 6, "emergency_access_allowed": true, "emergency_notification_reminder_schedule": "0 3 * * * *", "emergency_request_timeout_schedule": "0 7 * * * *", "enable_db_wal": true, "enable_websocket": true, "enforce_single_org_with_reset_pw_policy": false, "event_cleanup_schedule": "0 10 0 * * *", "events_days_retain": null, "experimental_client_feature_flags": "", "extended_logging": true, "helo_name": null, "hibp_api_key": null, "http_request_block_non_global_ips": true, "http_request_block_regex": null, "icon_blacklist_non_global_ips": true, "icon_blacklist_regex": null, "icon_cache_folder": "data/icon_cache", "icon_cache_negttl": 259200, "icon_cache_ttl": 2592000, "icon_download_timeout": 10, "icon_redirect_code": 302, "icon_service": "internal", "incomplete_2fa_schedule": "30 * * * * *", "incomplete_2fa_time_limit": 3, "increase_note_size_limit": false, "invitation_expiration_hours": 120, "invitation_org_name": "Vaultwarden", "invitations_allowed": true, "ip_header": "X-Forwarded-For", "job_poll_interval_ms": 30000, "log_file": null, "log_level": "info", "log_timestamp_format": "%Y-%m-%d %H:%M:%S.%3f", "login_ratelimit_max_burst": 10, "login_ratelimit_seconds": 60, "org_attachment_limit": null, "org_creation_users": "", "org_events_enabled": false, "org_groups_enabled": false, "password_hints_allowed": true, "password_iterations": 600000, "push_enabled": false, "push_identity_uri": "https://identity.bitwarden.com", "push_installation_id": "***", "push_installation_key": "***", "push_relay_uri": "https://push.bitwarden.com", "reload_templates": false, "require_device_email": false, "rsa_key_filename": "data/rsa_key", "send_purge_schedule": "0 5 * * * *", "sendmail_command": null, "sends_allowed": true, "sends_folder": "data/sends", "show_password_hint": false, "signups_allowed": false, "signups_domains_whitelist": "", "signups_verify": false, "signups_verify_resend_limit": 6, "signups_verify_resend_time": 3600, "smtp_accept_invalid_certs": false, "smtp_accept_invalid_hostnames": false, "smtp_auth_mechanism": "", "smtp_debug": true, "smtp_embed_images": false, "smtp_explicit_tls": null, "smtp_from": "***********************", "smtp_from_name": "Vaultwarden", "smtp_host": "*********************", "smtp_password": "***", "smtp_port": 25, "smtp_security": "off", "smtp_ssl": null, "smtp_timeout": 15, "smtp_username": "", "templates_folder": "data/templates", "tmp_folder": "data/tmp", "trash_auto_delete_days": null, "trash_purge_schedule": "0 5 0 * * *", "use_sendmail": false, "use_syslog": false, "user_attachment_limit": null, "user_send_limit": null, "web_vault_enabled": true, "web_vault_folder": "web-vault/", "yubico_client_id": null, "yubico_secret_key": null, "yubico_server": null } ``` </details> ### Vaultwarden Build Version 1.34.1 ### Deployment method Official Container Image ### Custom deployment method _No response_ ### Reverse Proxy Apache/2.4.62 ### Host/Server Operating System Linux ### Operating System Version AlmaLinux 9 ### Clients Web Vault ### Client Version 2025.5.0, multiple firefox and edge browsers ### Steps To Reproduce 1. Configure SMTP with no authentication method (SMTP_AUTH_MECHANISM=off, blank, etc) 2. Attempt to send test SMTP or user invite 3. Receive error: "SMTP client error: internal client error: No compatible authentication mechanism was found" ### Expected Result SMTP Sent without error ### Actual Result SMTP client error: internal client error: No compatible authentication mechanism was found ### Logs ```text [2025-07-22 10:28:46.972][request][INFO] POST /admin/invite [2025-07-22 10:28:46.974][vaultwarden::mail][WARN] No valid SMTP Auth mechanism found for '', using default values [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 220 mailout3.sunyocc.edu ESMTP Postfix<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] Wrote: EHLO 7de164919099<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF>250-8BITMIME<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] << 250-mailout3.sunyocc.edu<CRLF>250-PIPELINING<CRLF>250-SIZE 40960000<CRLF>250-VRFY<CRLF>250-ETRN<CRLF>250-ENHANCEDSTATUSCODES<CRLF>250-8BITMIME<CRLF>250 DSN<CRLF> [2025-07-22 10:28:46.979][lettre::transport::smtp::client::async_connection][DEBUG] server mailout3.sunyocc.edu with {EightBitMime} [2025-07-22 10:28:46.979][vaultwarden::mail][ERROR] SMTP client error: internal client error: No compatible authentication mechanism was found [2025-07-22 10:28:46.980][response][INFO] (invite_user) POST /admin/invite application/json => 500 Internal Server Error ``` ### Screenshots or Videos _No response_ ### Additional Context I am able to telnet to the postfix relay server and send a 'EHLO test.mail' and confirm the responses do not include an auth request. I have others non-authenticated clients able to send SMTP to this relay as well. I suspect not having any auth mechanism is failing a check for this function.

MrUnknownDE closed this issue

2026-04-05 21:22:03 +02:00

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Reference: github/vaultwarden#460