IMAP4 Authentication Failure - After a while...

Markus Walter 40 Reputation points
2024-01-16T14:54:28.1966667+00:00

Hi there, we´ve a issue with one Mailbox and connection thru IMAP.

After i restart both onpremise Server i can login with IMAP to this Mailbox. Then it takes a while and it isn´t possible. It seems that it is specific to this Mailbox.

I did a test with a new created Mailbox there isn´t an issue.

In the IMAP Logs i can find this lines:

xxxxx*****,"R=""64yd NO LOGIN failed.\r\n* BYE Connection closed. 14"";Msg=Proxy:xxx.xxxx:1993:SSL;ErrMsg=ProxyNotAuthenticated"

Any Ideas?

Best Regards Markus

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Kael Yao-MSFT 37,691 Reputation points Microsoft Vendor
    2024-01-17T01:29:54.62+00:00

    Hi @Markus Walter,

    After i restart both onpremise Server i can login with IMAP to this Mailbox. Then it takes a while and it isn´t possible. It seems that it is specific to this Mailbox.I did a test with a new created Mailbox there isn´t an issue.

    Are you testing in the same network? If not I would suggest switching to another network to see if it is a network issue. If this is not the case, please run the following cmdlet in Exchange Management Shell on the Exchange servers to check if it will return error messages:

    Test-ImapConnectivity -ClientAccessServer Contoso12 -MailboxCredential (Get-Credential contoso\kweku)
    
    
    

    Besides, please also have a check in application log on Exchange servers to see if you can find error or warning events which may be related.


    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".  Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.


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