Sometimes, a custom application which uses HTTP as a carrier protocol has an incorrect request header. In this situation the ProxySG returns 400 (HTTP return code). To address this, follow this procedure (particularly with an explicit proxy).
In this example, "Egnyte" is a user agent. Other parameters in the example are optional, such as AD group and user agent.
Do the following:
https://proxyIP:8082 > Configuration > Policy files > choose Local policy file > from the drop down menu choose Text Editor > add the following policy
realm=Any_realm_name group="Any_ream_name\Any-Group" request.header.User-Agent="Egnyte" detect_protocol(none)
Any_realm_name is the realm that's being used to authenticate users,
Any-Group is the AD that this will be allowed for, and "Egnyte" is the user agent.
For more information on "http tolerant-request-parsing," please check KB article FAQ2220, and/or the CLI guide.