Consider the following scenario:
1. An Apache-based application is published by Microsoft Forefront Unified Access Gateway 2010 (UAG) using the "Other Web Application" template.
2. A user attempts to access the application from a browser that use HTTP/1.0.
In this scenario, the backend application will reply back with “connection: close” and will terminate the SSL connection with close_notify. UAG, instead of sending that reply back to the client, will either send back a 500.htm error or Error 37: "An unknown error occurred while processing the certificate".
UAG does not support a client browser sending HTTP 1.0 with an Apache backend when the Apache server is setup to use HTTP 1.0.
To work around this issue, enable HTTP 1.1 on the client browsers.