I just downloaded the latest version of eM Client to install on my Windows 11 laptop. The first account I tried to add - my Gmail account - will not complete the set up. In the New Account dialog, after entering all of the information and checking the boxes I want to include in the account, I click the Finish button, a browser window opens (in Edge Chromium) to sign in to my Google account. I click my Google account. I get the screen telling me what eM Client wants to do and click the Allow button. But then I get a screen that says, " Something went wrong. Sorry, something went wrong there. Try again." My only option in that screen (besides closing the browser tab) is to click Next, which brings me to the Google Account overview page. I am getting the same behavior when I set my default browser to Firefox.
Odd thing is, I just got done successfully setting up eM Client on my Android phone and everything works fine there - even added two other accounts - POP and IMAP.