If mail is not being delivered, first determine whether the issue is inbound, outbound, or both. That makes the troubleshooting path much faster.
- Check MX, SPF, DKIM, and other relevant DNS records.
- Confirm the sending or receiving address is correct.
- Look for bounce messages or SMTP errors.
- Verify mailbox quota and account status.
- Review recent DNS changes and allow for propagation.
When you contact support, include the affected address, approximate send time, recipient domain, and any error text. Those details are usually needed to diagnose the problem.