- Check the cable connection from the desktop to the mailbox and make sure it is securely connected.
- Check the status of the mailbox by running power cycle on the device.
- Log in to the mailbox and make sure the system time is accurate.
- Verify that the settings configured in the mailbox, such as SMTP, POP, IMAP, etc., are correct.
- Check the Exchange service on the server to make sure it is running without any errors.