Mail that never arrives has a small set of causes.
1. IS THE MAILBOX FULL?
cPanel > Email Accounts shows usage. A full mailbox rejects mail and the sender gets a bounce.
2. IS THE ACCOUNT OVER ITS DISK QUOTA?
A full hosting account stops delivering mail regardless of the individual mailbox quota. Check the cPanel statistics panel.
3. IS IT IN SPAM?
Check the Spam or Junk folder, both in webmail and in your mail client. A low spam threshold filters legitimate mail.
4. DO THE MX RECORDS POINT HERE?
If they point at another provider, mail goes there. Check with an MX lookup.
5. IS EMAIL ROUTING CORRECT?
cPanel > Email Routing. If it is set to Remote while your MX points here, or the reverse, mail vanishes into the wrong place.
6. IS A FILTER MOVING OR DISCARDING IT?
Check cPanel > Email Filters and your webmail filters.
7. DID IT REACH US AT ALL?
Ask the sender for the bounce message. That usually names the cause precisely.
