We are getting connection refused error while trying to access the server via pop. Please check the below logs.
26 01:57:18 host2 dovecot: pop3-login: Maximum number of connections from user+IP exceeded (mail_max_userip_connections=3): user=, method=PLAIN, rip=220.127.116.11, lip=18.104.22.168
Edit /etc/dovecot.conf and check the parameter “mail_max_userip_connections” was set to 3.
mail_max_userip_connections = 3
Increased it to a higher value and the issue got fixed.