Cannot login from console via IMAP on GWIA

Hello everyone,

My customer tries to login via IMAP to the GWIA (12.0.1), the error is "NO LOGIN GroupWise login failed".
Error occurs if customer uses console (telnet, openssl). From IMAP client (Outlook) just works fine.

I found this TID:
Support | Unable to login in a GroupWise mailbox via IMAP4 or POP3.
but customer said that option UserID@iDomain at "Allowed address formats" in C1 is enabled.

logs:

GWIA
13:36:54 F3B7 5832 "***" Client A20 "LOGIN my_user"
13:36:56 F3B7 5832 "***" Server A20 "NO LOGIN GroupWise login failed"

POA
13:36:54 EEB7 *** NEW APP CONNECTION, Tbl Entry=63, Check
ID=1358082874
13:36:54 EEB7 C/S Login GWIA/Imap ::GW Id=my_user :: 10.10.200.15
[10.10.200.19]
13:36:54 EEB7 *** APP DISCONNECTED, Tbl Entry=63, Check ID=1358082874

Any suggestions please?

Emil