How to Diagnose a cPanel Mailbox That Stops Receiving New Messages

A mailbox may stop receiving mail because it reached quota, a filter moved messages, DNS points elsewhere, or the receiving server deferred delivery.

What to check

Check mailbox and account quotas, mail delivery logs, filters, MX records, and the sender’s SMTP response. Preserve a sample timestamp and recipient while avoiding disclosure of message contents.

Recommended next step

Resolve the identified quota, routing, or filter issue and send a controlled test from outside the domain. Informatix Systems can review cPanel email and DNS configuration.