SMTP Configuration

Help
1

Hello

I was settings up vaultwarden in my org, and everything was working perfectly, expect the SMTP configuration.

When trying to send mail we get the error “[vaultwarden::mail][ERROR] SMTP error: response error: incomplete response”

I suspect this is because of o365 SMTP relay gives no response even when you correctly connect.

Config:

Screenshot 2025-01-06 090613
Screenshot 2025-01-06 0906131285×973 28.7 KB

Then i thought i could just use our on-prem SMTP relay. Which uses host based filtering, but then it dosen’t give a login method.

So VaultWarden throws the error:
2025-01-06 09:08:15 [2025-01-06 08:08:15.391][lettre::transport::smtp::client::async_connection][DEBUG] << 250-smtp.fmk.dk Hello [10.32.13.140]250-TURN250-SIZE250-ETRN250-PIPELINING250-DSN250-ENHANCEDSTATUSCODES250-8bitmime250-BINARYMIME250-CHUNKING250-VRFY250 OK

2025-01-06 09:08:15 [2025-01-06 08:08:15.392][vaultwarden::mail][ERROR] SMTP client error: internal client error: No compatible authentication mechanism was found

Config (couldt not uploade 2 images, so created it as a table instead):

Setting Value
Enabled True
Use sendmail False
Sendmail commaind
Host smtp.example.com
Secure SMTP starttls
Port 25
From Address srvcvaultwarden@example.com
From Name vaultwarden Vaultwarden
Username
Password
SMTP Auth Mechanism
SMTP Connection TimeOut 30
Server name sent during HELO
Embed images as email attachments True
Accept invalid certs True
Accept Invalid Hostnames False

I have tried diffrent Auth methods non worked.

So i was wondering if any of you have run into one of the errors and knew how to fix it, or just knew in which direction to look.

2
3

Thank you.

Think i turned ideotic while settings this up.

So the test returned 1, so i started troubleshooting the connection between vaultwarden and m365.
And ended up realised i forgot added all the IP’s to the allow group in the FW.

So when vaultwarden tried to conenct to exchange online, the destination was denied, and sinkholed.

So you know first step is always to check connection between to points before anything else.