Overview

Outlook plugin fails to connect and the debug logs are showing the following error in the OutlookAddInCore log:

OutlookAddInCore", "Error: Failure whilst performing Web Service Version with error: System.ServiceModel.ProtocolException: The remote server returned an unexpected response: (400) Bad Request. ---> System.Net.WebException: The remote server returned an error: (400) Bad Request.

Environment

• GFI MailEssentials
• Outlook plugin
• All supported environments

Root Cause

HTTP redirect in Internet Information Services (IIS) is not allowing the authentication to occur with the MailEssentials_Service. Disabling the redirect allows the connection to complete.

Resolution

1. Open the IIS Manager.
2. Locate the website with the MailEssentials_Service Virtual Directory.
3. Select the HTTP Redirect.
4. Uncheck the redirect if applicable.
5. Perform an IIS reset and retest the connection.