Roundcube IMAP Error Authenticate

Hello, i recently updated from Plesk 12.0 to 12.5,

i had following error:

[26-Mar-2016 05:36:02 +0100]: <pm6po603> IMAP Error: Login failed for t0mi@MYHOST from MYIP(X-Real-IP: MYIP,X-Forwarded-For: MYIP). AUTHENTICATE CRAM-MD5: in /usr/share/psa-roundcube/program/lib/Roundcube/rcube_imap.php on line 197 (POST /?_task=login?_tas$

after googling and found this: https://kb.plesk.com/en/125401

i get the same error with PLAIN:

[26-Mar-2016 06:11:11 +0100]: <pm6po603> IMAP...

Roundcube IMAP Error Authenticate