Can you launch a browser, say Chrome or Edge, and try these two links:

https://prodldfp.proseries.com/fa/2020/windows/proseries_core/S2020COI.xml

https://perdldfp.turbotax.com//fa/2020/windows/proseries_core/S2020COI.xml

They are both to the same file.. it should look something like this:

My prediction is that the first will fail, and the second will succeed. Reason being.. we're seeing some routers/firewalls/ISP blocking our proseries.com domain.  I can get into the technical details of why.. but we're working on it.

In the meantime, if that test proves out, we can work on getting you going.  By chance are you a Comcast/Xfinity user?