Use Connection Doctor to Diagnose Mac OS X Mail problems
This article will go over diagnosing email connection problems with the connection doctor within Mail.
- Open Mail.
- Navigate to Window > Connection Doctor.
- A window will open with a list of the SMTP and POP servers for all accounts in Mail.
If there is a red dot next to the server, please make sure your settings are correct following: How do I configure Mac OS X Mail for my Email Accounts?