Constant LDAP/OCID errors in Outlook – Timeout or Server Issue?

[CBCUN]

Hi everyone,

I’m running a split Cloudron environment and experiencing constant password prompts in Outlook (IMAP), even though the credentials are correct.

Setup:

Server A: Cloudron Mail Server

Server B: Cloudron User Management (LDAP)

The Issue:
Outlook frequently pops up a login window. It seems like the Mail Server is failing to verify credentials with the LDAP Server in time.

Questions:

Could this be a timeout issue during the LDAP lookup between the two servers?

Has anyone else faced "credential looping" with Outlook in a multi-server Cloudron setup?

Which specific logs should I check on Server A to confirm an LDAP handshake delay?

Thanks for any help!

[nebulon]

To narrow down the issue a bit, can you create a mailbox on Server A which uses a local account to authenticate and then setup Outlook for that mailbox? If this suffers the same issue, then it is not related to the LDAP binding between those two Cloudrons.

[CBCUN]

Hello,

Apologies for the late reply. Things have been rather busy.
The initial setup of the mailboxes is working. It seems, however, that timeouts or errors occur during regular mailbox checks (IMAP). Every now and then, you can see the mail service restarting.

Perhaps there are too many requests at once, or does the password check take too long (does Server B ‘Mailserver’ check with Server A on every retrieval to see if it’s authorised, or is that only processed on Server B?).

Best regards,
Christian

[nebulon]

If the client (outlook) reconnects it would do the authentication again and then we have to validate those credentials at the source, so Server A in your case.

But if the mail server is restarting that is some other clue which might actually be the root cause. When that happens do you see anything in the mail service logs why it restarted? Maybe it ran out of memory or did it crash?

[CBCUN]

So, update on this topic.

We change the Mailbox owner from LDAP Group (Server A) to local group (Server B - Mailserver).
Outlook and Auth problems stops immediately.

Greetings,
Chris

[nebulon]

That is a good hint, so something is not working reliably with the ldap connection then. Can you check on Server A if you hit any rate-limits? You should see them with journalctl -k | grep CLOUDRON_RATELIMIT_LOG on Server A