NuGet feed not working

We just installed a new instance of Orchestrator v 2020.4.2. When I connect a studio machine (v2020.4.3) to orchestrator and try to manage packages, the Orchestrator Host feed returns the below error. I have stripped the URL, but the rest of the error message is true.

package source orchestrator host has encountered the following error: the v2 feed at XXX returned an unexpected status code ‘403 Forbidden’

Any advice?

Possible firewalls blocking the connection or proxy settings?

Should have mentioned that the production server (v2018.4.3) has no issues, and we made no configuration changes to support the production environment during install of that environment.

Is there a way to test/debug to determine if it is a firewall issue?