A user account is configured in Mimecast for Outlook. Once the details have been saved, the error "This is not a valid Mimecast account." is displayed.
The configured user account cannot connect and download the Application Settings and capabilities from Mimecast.
- Re-enter the user credentials correctly.
- If using a Proxy Server, confirm that the details have been entered to allow HTTPS traffic to Mimecast.
- Confirm that the Mimecast Windows process has started.
- Verify the Application Settings that apply to the user's email address.