Forwarded to devs IDN Domain Mail Password Wrong

[flth]

User name: flth

TITLE

IDN Domain Mail Password Wrong

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE

Ubuntu 18.04.4, Plesk Obsidian
Version 18.0.25 Update #1

PROBLEM DESCRIPTION

After updating to Plesk Obsidian the mail password on a IDN domain is always reported as wrong. Can't login, can't get emails on this domain.
mail log just shows (censored some parts with xxx)
server authpsa[3023]: No such user 'info@rechtsanwälte-xxx.de' in mail authorization database
server courier-pop3d_ LOGIN FAILED, [email protected], ip=[ffff:82.83.xxx.xxx]

Plesk mail repair doesn't show any errors. Client side it just shows wrong password in logs as well. Tried with idn domain same as with xn-

It worked well in Plesk 17. A new password was tried as well.

STEPS TO REPRODUCE

not able to test a reproducing. What was done:
update OS to Ubuntu 18.04, updated Plesk to 18

ACTUAL RESULT

not able to fetch mails from these accounts

EXPECTED RESULT

it should work like it did in Plesk 17

ANY ADDITIONAL INFORMATION

Issue - IDN Domain Mail Password Wrong

YOUR EXPECTATIONS FROM PLESK SERVICE TEAM

Help with sorting out

 

[IgorG]

Thank you!
The problem is known as PPP-46196.
Could you, please, confirm that Thunderbird could successfully authenticate for the same mailbox?