Issue IMAP: Unable to login / imap-login: Disconnected

[bb74]

Hello,

yesterday I changed the sending IP from my Plesk Obisdian Server.
Since that I cannot login via IMAP:
Oct 9 17:02:32 balin dovecot: imap-login: Disconnected (auth failed, 1 attempts in 2 secs): user=<info@xxx-xxx.de>, method=CRAM-MD5, rip=46.183.xxx.xxx, lip=89.163.146.83, TLS, session=<Hi/UPD6xGHsut2cR>

Any ideas? I restarted the dovecot server, I set a new password, but no login...