Rainloop, Authentication Failed

Hello, Whenever i try to login for webmail on rainloop it says Authentication Failed. Someone told me to use this command “journalctl -f | grep dovecot”. Please see the response.

May 27 13:11:01 AMS-324952 auth[394721]: pam_unix(dovecot:auth): check pass; user unknown
May 27 13:11:01 AMS-324952 auth[394721]: pam_unix(dovecot:auth): authentication failure; logname= uid=0 euid=0 tty=dovecot ruser=faisal@abc.com rhost=51.15.13.121
May 27 13:11:05 AMS-324952 dovecot[309838]: imap-login: Disconnected (auth failed, 1 attempts in 4 secs): user=faisal@abc.com, method=PLAIN, rip=51.15.13.121, lip=51.15.13.121, TLS, session=

Please help me. I’m unable to check emails.