Multiple Google Accounts Conflicts
You can only sign into Google (any app) with one Google Account at a time. Sometimes this can create conflicts within a browser or app.
For example, if you have a personal Gmail account, you will need to logout before using your @southern.edu account to access your SAU Google Apps resources. More information about switching accounts can be found here:
Alternatively, an easy workaround is to use a separate browser for the different accounts.