After changing your Temple password, accessing your Temple email through Mac Mail may fail. There are a number of reasons this may happen. The primary reason is that there is a delay in the synchronization of your new Temple password and the gmail IMAP (incoming) mail server. An additional issue may be that the gmail SMTP (outgoing) password was not updated in the Mail app.
If you need to send or check email urgently, you should be able to access it through TUmail.
To identify which one is failing, open Mail, and from the menu bar at the top, choose Window --> Connection Doctor. The one(s) with the red dot next to them are the ones that are failing to connect (you may have to scroll to see all of the servers).
If it is just the Google IMAP server, please give it some time for the passwords to synchronize. Please submit a TUhelp ticket and ask how long the syncronization will take (and perhaps why there's a delay at all).
If it is the SMTP server smtp.gmail.com associated with your account, double click the server in the list. In the "Account Information" portion, provide the server smtp.gmail.com and then click the Advanced tab. Specify port 587 and check Use SSL. Do NOT allow insecure authentication. For Authentication choose "Password", and provide your full Temple email address as the username, and your Temple password as the password.