It’s definitely fine on 2 machines with the same settings. The machine that is failing is on Win7 and .NET Framework 4.7.1 (version 4.7.02558).
Now that I think of it I was testing TLS/Cipher settings a few weeks ago, it hasn’t affected anything else, but I’ll try restoring those to see if it helps. I think it’s highly likely that’s the issue. I’ll post my results here in case anyone else runs into the problem.