Note: The code above is not related to Fiddler Everywhere and looks like an implementation used with the FiddlerCore library.
Based on your issue description, it sounds like the process you are trying to capture is not respecting the custom proxy you are setting on port 8877. HTTP Debugger is a sniffer and not a proxy (based on their product page), which explains the difference in the behavior.
Handlerborsodimario
I made some progress, if I paste the request url in a browser, I get the modified response, but if I launch the software i'm tryna bypass it's not modifing the response, or dunno. Fiddler everywhere can't even see the process's request, but http debugger pro does.
here's my code, am I doing something wrong?