Subscription Management "cannot reach server" error through proxy

Trying to activate with my credentials but getting a “cannot reach server” error:

I’ve gone through the knowledge base article about this and none of the listed solutions apply.

My company runs a cloud-based, mostly transparent proxy. I don’t have (and I don’t usually need to) configure a proxy explicitly, it’s just there. (That’s the transparent part of our proxy.)

I say it’s “mostly” transparent because it does do SSL/TLS interception, which will wreck an application that verifies the certificate chain–as I suspect ManyCam is now doing?

I have successfully activated in the past so wondering if this is a newish behavior of ManyCam?