Cannot login into Vaultwarden with new computer and Yubikey / OTP

[deajan]

Prerequisites

• I have searched the existing Closed AND Open Issues AND Discussions
• I have searched and read the documentation

Vaultwarden Support String

Your environment (Generated via diagnostics page)

• Vaultwarden version: v1.36.0
• Web-vault version: v2026.4.1
• OS/Arch: linux/x86_64
• Running within a container: true (Base: Debian)
• Database type: SQLite
• Database version: 3.51.3
• Uses config.json: false
• Uses a reverse proxy: true
• IP Header check: true (X-Real-IP)
• Internet access: true
• Internet access via a proxy: false
• DNS Check: true
• TZ environment: Europe/Paris
• 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

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_idle_timeout": 600,
  "database_max_conns": 10,
  "database_min_conns": 2,
  "database_timeout": 30,
  "database_url": "****************",
  "db_connection_retries": 15,
  "disable_2fa_remember": false,
  "disable_admin_token": false,
  "disable_icon_download": false,
  "dns_prefer_ipv6": 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": 180,
  "email_token_size": 12,
  "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": "'^(192\\.168\\.[0-9]+\\.[0-9]+)$'",
  "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": "NetPerfect",
  "invitations_allowed": true,
  "ip_header": "X-Real-IP",
  "job_poll_interval_ms": 30000,
  "log_file": "/data/vaultwarden.log",
  "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": true,
  "org_groups_enabled": true,
  "password_hints_allowed": true,
  "password_iterations": 600000,
  "purge_incomplete_sso_auth": "0 20 0 * * *",
  "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": true,
  "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": true,
  "signups_domains_whitelist": "*************,***********,********************,********,********************,*******************,*********************************,******************",
  "signups_verify": true,
  "signups_verify_resend_limit": 6,
  "signups_verify_resend_time": 3600,
  "smtp_accept_invalid_certs": false,
  "smtp_accept_invalid_hostnames": false,
  "smtp_auth_mechanism": null,
  "smtp_debug": false,
  "smtp_embed_images": true,
  "smtp_explicit_tls": null,
  "smtp_from": "*******************",
  "smtp_from_name": "************************************",
  "smtp_host": "*********************",
  "smtp_password": "***",
  "smtp_port": 587,
  "smtp_security": "starttls",
  "smtp_ssl": null,
  "smtp_timeout": 10,
  "smtp_username": "*******************",
  "sso_allow_unknown_email_verification": false,
  "sso_audience_trusted": null,
  "sso_auth_only_not_session": false,
  "sso_authority": "",
  "sso_authorize_extra_params": "",
  "sso_callback_path": "*****://*********************************************",
  "sso_client_cache_expiration": 0,
  "sso_client_id": "",
  "sso_client_secret": "***",
  "sso_debug_tokens": false,
  "sso_enabled": false,
  "sso_master_password_policy": null,
  "sso_only": false,
  "sso_pkce": true,
  "sso_scopes": "email profile",
  "sso_signups_match_email": true,
  "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

v1.36.0

Deployment method

Official Container Image

Custom deployment method

No response

Reverse Proxy

haproxy 3.1

Host/Server Operating System

Linux

Operating System Version

RHEL9.8 x64

Clients

Web Vault, Desktop

Client Version

2026.4.1

Steps To Reproduce

1. Open webvault
2. Enter Email and password
3. Browser asks to touch my yubikey 5 NFC
4. Touch the yubikey

Also happens via BW client 2026.5.0.
Also happens when I use an OTP code to connect (have configured my yubikey to also have an OTP code for Vaultwarden).

Expected Result

Login ;)

Actual Result

Got error message in french (my locale) which roughly translates to inalid verification code.

Une erreur est survenue.
Code de vérification invalide

Logs

Since I cannot access my vault, I'm having a fun time connecting to my server to fetch logs yet.

Screenshots or Videos

No response

Additional Context

No response

[deajan]

Finally got the culprit. I had IPv6 connection issues, and the "welcome mail" for new devices couldn't be sent to my SMTP relay. Once my ISP got his IPv6 trouble sorted out, I could connect to Vaultwarden again.
So, sorry for the noise.

I would have a remark though @BlackDex
Perhaps the error message when the email cannot be sent could be improved in case of a new device first connection with 2FA, because the diagnostic would have been quite easier and the UX less scary...
I mean both my yubikeys and my rescue OTP didn't work, so it got quite scary until I got to use VW on an already known device.
Thanks.