Kopano webapp and Nextcloud yes, thunderbird no go

I have a strange problem, I have a few mail domains off which one refuses to work with Thunderbird.
The two users I added for this domain can’t get an account configured in Thunderbird, username or password credentials wrong. But with these same credentials I can login into the Kopano webapp, send and receive email and access Nextcloud. So everything seems right, only getting an acount configured on the Thunderbird clients keeps giving me the mentioned errors. Other domains work nicely with Thunderbird, what can be the problem or do I overlook?

Hi @jos,

You still need to enable IMAP access for the user account in the UMC.

Ah yes!, that’s it. So stupid to overlook this setting for these two account.
Thanks for pointing me to this.