Issue MailEnable: invalid username or password with more than 1 IMAP clients

[domml]

Dear Plesk community,

I am running Plesk Obsidian 18.0.42 Update #1 on my Windows Server 2019 1809 with MailEnable Standard 10.34.
I have configured an [email protected] inbox in the Plesk mail settings and configured all settings regarding mail the best I could.
In the MailEnable settings I found that the maximum number of connections to one address is configured to "unlimited".

However, whenever I try to connect more than one mail client, I get the "invalid username or password" error message on whichever client I try to connect with last.

The MailEnable log shows this as well:
LOGIN LOGIN [email protected] "********" 4 NO LOGIN Failed - Invalid username or password. 51 43

I am 100% sure the credentials are correct since they do work if the respective client is the only one subscribed to the IMAP inbox.
The issue persists even if both clients have different public IP adresses.

I need to have several clients connected since my use case is Thunderbird client on a Windows Desktop along with Gmail on an Android mobile device. It's also planned to access the inbox from Thunderbird on a Linux Laptop in the future.

I hope you can help me with this issue and would like to thank anyone willing to investigate this with me in advance.
I'd also be open to having a look at this via third party communication apps - just dm me for that.

Greetings,
Domml

 

[Nik G]

hello @domml ,

the Plesk itself has no functionality to limit simultaneous connections count even ME has such functionality.

You can check this settings in ME msc by right click on IMAP service > Properties


What about POP protocol, is it suffer the same problems or not ?