Most email failures are wrong settings or a full mailbox. Start by sending a test using cPanel Webmail — if webmail works, the issue is in your mail client.
- In your client (Outlook, Apple Mail), confirm the incoming/outgoing server is
mail.yourdomain.com, the username is your full email address, and SMTP authentication is enabled. - Use the secure ports: IMAP 993, POP3 995, SMTP 465 (SSL/TLS).
- In cPanel Email Accounts, check the mailbox is not over quota and reset the password if needed.
- If your IP got blocked after wrong-password attempts, your access may be firewalled.
If webmail itself fails or mail is rejected, open a ticket with the bounce message.