Modified GET receives no response

Hello,

Just for context, I am running two VMs. One serves as a router for the other. I have MITMproxy installed on the router. I can access the internet and what not successfully from my client VM. The script successfully modifies the GET request and changes the header and host to a different address. In this case, it changes “www.google.com” to “www.stackoverflow.com”.

However, I do not receive a response when my script modifies the request. Any ideas why? I tried playing with iptables rules, but I feel this isn’t the issue since I can receive responses through the proxy as long as I don’t modify it.

Update, I have tried running mitmproxy on my local machine as well and routing my own traffic through it, when I modify a GET request via the mitmproxy ui for Windows, I still do not receive a response, my web browser just sits and loads.

FIXED: Had to add the --set upstream_cert=false when running.

Thanks