Did you come across any issues with eM Client recently? We have received several reports regarding eM Client authentication problem with Gmail servers via OAuth.
eM Client, Gmail and OAuth
Some of our users have reported problems while using eM Client and authenticating with Gmail servers. The application notifies users about JavaScript being disabled in default browser.
Our developers have inspected this in detail and discovered that the embedded OAuth features are being blocked by Gmail servers for Internet Explorer. Since IE is currently the default browser for eM Client 6, this has been marked as the root of this problem. Please note that we're working on the new version 7 which will feature Chromium to replace IE as the default browser.
We'll be including a workaround for the issue in the next update for version 6 available in the Check for Updates option or you can download the update below if you're experiencing the issue.