I am trying to browse websites through a proxy that intercepts the TLS connections and signs the certificates using a private CA certificate.

If I'm using only a root CA certificate, setting it on my proxy as well as in the OS's certificates store, I can browse the internet without any issues. The chains in this case would be: Root CA -> Server Certificates

However, my setup mandates that I use an intermediate CA on the proxy. The chains in this case would be: Root CA -> Intermediate CA -> Server Certificates If I add an intermediate CA to the proxy and the root CA to my OS's certificates store, I get the following error:

" Secure Connection Failed An error occurred during a connection to www.youtube.com. Peer’s certificate has an invalid signature. Error code: SEC_ERROR_BAD_SIGNATURE

"

I'm using Firefox 82.0.2 on Windows 10.

How can I get more details on why it's failing? I've tried looking in the "Security" tools tab, but I see only this error ID.

Thank you, Cosmin