Why don't non-standard http headers get through?

Question

Computer networks

In response to a request, the server sends a response with non-standard http headers. Usually they come, but on one computer the situation steadily arises - the request is executed, but the response comes without these headers. What could be the reason?

Answer 1

Is there any proxy in the chain of passing the response to it:
- standalone
- placed directly on this PC (including, for example, from an antivirus)
- anti-virus plugin
- turbo mode that passes all traffic through some compression node
?

Answer 2

Have you looked at requests through Fiddler2? www.telerik.com/fiddler In Composer mode?

Answer 3

Symantec endpoint protection works on the PC, I tried to disable it - without effect. The Internet connection, as I was told, is direct, without a proxy. But the PC is in the enterprise network. M.b. there's a special gateway...