[bug]: Unable to send emails to Gmail "Unexpected SMTP server response"

[CEbbinghaus]

What happened?

It seems that whenever I try and send an email to a gmail inbox it fails to send with the error:

InvalidRecipientsException: Invalid recipients were provided for the message: '727' (550 5.1.2 Mailbox does not exist.
). --> Unexpected SMTP server response. Expected: 250, actual: 550, whole response: 550 5.1.2 Mailbox does not exist.
 
Failure code: 8a7c

This is generated by outlook but it seems that the SMTP server itself is returning an unexpected status code

How can we reproduce the problem?

Sending an email to any gmail address

Version

v0.9.x

What database are you using?

RocksDB

What blob storage are you using?

None

Where is your directory located?

LDAP

What operating system are you using?

Docker

Relevant log output

2024-08-25T11:02:58Z INFO SMTP connection started (smtp.connection-start) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354
2024-08-25T11:02:58Z INFO SMTP EHLO command (smtp.ehlo) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, domain = "PU4P216MB2134.KORP216.PROD.OUTLOOK.COM"
2024-08-25T11:02:59Z INFO TLS handshake (tls.handshake) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, listenerId = "submission", version = "TLSv1_3", details = "TLS13_AES_256_GCM_SHA384"
2024-08-25T11:02:59Z INFO Authentication successful (auth.success) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, accountName = "[username]", accountId = 38, type = Individual
2024-08-25T11:02:59Z INFO SMTP MAIL FROM command (smtp.mail-from) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, from = "[my email]"
2024-08-25T11:02:59Z INFO Mailbox does not exist (smtp.mailbox-does-not-exist) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, to = "[valid-email]@gmail.com"
2024-08-25T11:03:05Z INFO SMTP connection ended (smtp.connection-end) listenerId = "submission", localPort = 587, remoteIp = 40.99.72.125, remotePort = 3354, elapsed = 6446ms

Code of Conduct

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[devfbe]

I just successfully tested it with the most recent stalwart mail server, no issue delivering emails to gmail - at least for me (everything on rocksdb).

[mdecimus]

If you are seeing the smtp.mailbox-does-not-exist error when delivering to a Gmail account it means that Stalwart is treating the gmail.com domain as local. Probably this is happening because your LDAP local domain query is incorrectly configured.

[CEbbinghaus]

It is strange that this would only happen with gmail if gmail isn't specifically named. Is the "LDAP local domain query" this SMTP > Outbound > Routing > Next Hop setting?

I wasn't able to find anything else that looked like its right

[CEbbinghaus]

my LDAP domain bind was defined as "(&(|(objectClass=posixAccount)(objectClass=posixGroup))(|(mail=*@?)(mailAlias=*@?)))" same as with the docs. The problem was that that one of my users has a mail attribute with their gmail email (for sending emails to the user) which messed with stalwart. Removing that attribute and restarting stalwart has since fixed that problem