1. Navigate to testconnectivity.microsoft.com.

   

2. You should see the above screen; select the product you want to test. For example, Outlook Anywhere (Outlook Web Access), and click on Next.
3. Fill out the following form. In the case of Outlook Anywhere, enter your credentials:
4. Fill out the verification code and click on Perform Test in the top right.

A connectivity test will then run, letting you troubleshoot your connection to the service.