If a mailbox cannot send or receive email, use these checks.
1. Sign in to cPanel and confirm that the mailbox exists and has not exceeded its storage quota.
2. Check that you are using the correct email address and password. If in doubt, reset the mailbox password in cPanel and update your email application.
3. If you use an email application, verify the incoming and outgoing mail server names, ports, and encryption settings shown by your hosting service. Do not guess these values.
4. Check whether the problem affects webmail as well as your email application. This can help narrow down the source of the problem.
5. Confirm that the domain’s mail DNS records are correct, especially if you recently changed nameservers.
6. Try sending a test message to another address and check for a bounce-back or error message.
If the issue remains, open a support ticket and include the affected domain, approximate time, exact error text, and whether sending, receiving, or both are affected. Do not include passwords or private message contents unless absolutely necessary.
