I documented the problem, and my solution for it here:
https://stackoverflow.com/questions/66752310/error-winhttp-name-not-resolved-when-using-dbghelp-as-a-service/66763476#66763476
In summary: WinHttp is used by dbghelp when it runs as a service (it detects this automatically), and it doesn't support https at all in this mode. This is a problem if you try to proxy the MS symbol server (and probably others), because it redirects (even from http as opposed to https) to https cdn for the actual files. The work around for this is either to setup a http https proxy, OR use an older version of dbghelp, which still supports forcing WinInet instead of WinHttp, which CAN connect to https (assuming credentials).
After I setup this pySymProxy to run under IIS (using a properly credentialed domain account), and switched to the old dbghelp, and applied the DBGHELP_WININET=1 env var, it works for all servers I can access normally.
Of course if your https server will actually ask for login details then WinInet will not work, I don't know anything about this though.
I documented the problem, and my solution for it here:
https://stackoverflow.com/questions/66752310/error-winhttp-name-not-resolved-when-using-dbghelp-as-a-service/66763476#66763476
In summary: WinHttp is used by dbghelp when it runs as a service (it detects this automatically), and it doesn't support https at all in this mode. This is a problem if you try to proxy the MS symbol server (and probably others), because it redirects (even from http as opposed to https) to https cdn for the actual files. The work around for this is either to setup a http https proxy, OR use an older version of dbghelp, which still supports forcing WinInet instead of WinHttp, which CAN connect to https (assuming credentials).
After I setup this pySymProxy to run under IIS (using a properly credentialed domain account), and switched to the old dbghelp, and applied the DBGHELP_WININET=1 env var, it works for all servers I can access normally.
Of course if your https server will actually ask for login details then WinInet will not work, I don't know anything about this though.