How do I troubleshoot an issue with email sync on a mobile device?

Verify the email address has been entered correctly.
Verify the device is connected to a reliable Wi-Fi signal or mobile network.
Check server settings for the incoming and outgoing server configuration.
Check that the correct ports are open.
Check for any Firewall blocks for the email or traffic.
Disable and re-enable the account if necessary.
Try a manual sync if available.
Check the memory available on the device and free up more if needed.
Update the mail client to the latest version if available.
Check if there are any hardware issues.
Check if similar issues occur on other devices.
If all else fails, contact technical support.