Hi Noble,
Thank you for providing the detailed information to us. According to the error message “The server cannot be reached to validate your password”, this issue may occur because a proxy firewall blocks HTTP port 80. To test the issue, please unblock port 80 outgoing on the network edge or proxy edge.
This issue also can be caused by a security application, software or possible network adapter or antivirus installed on the affected local MAC machine. If the issue persists after unblocking port 80, I suggest you also check the security programs.
Thanks,
Mindy Pan