In case CS0956896 we have spent hours togehther with your support to find out why we could no longer login from private PCs into the Access Console Fat Client. The reason was that the certificate chain was missing Root and Intermediate Certs on the PAM server. But the error message showed misleading "connection error" and something with "re-detect my proxy settings".
This certificate check seems to be new in the fat client since 20.2.x. Or one of the most recent updates of the PAM server did not keep the certificates we had on that system. We have installed this test system 2 years ago and I am not sure if we installed the complete chain on /appliance or if we've forgot that.