I was also having this issue in my Outlook. Version 2602 Compilation 19725.20172.
But I have a total of 3 gmail accounts. 2 of them are ok with no errors. The other one started to have this issue recently. I removed the account and added it again, but it was not possible to complete the new account process.
It goes to the browser window to confirm my authorization, I clicked next and it opens an error page with ERR_CONNECTION_REFUSED. Meanwhile in Outlook, the email configuration window returned the same feedback, an error, and no way out.
But when I tried the process again, when in the browser window from Google authorization screen, I didn't tick the "authorization to read my emails" box. This last time I did, and the following page was an error too. But Outlook did add the account and I was able to read and send emails.
On the other hand, as I was typing this, I noticed my two "good" accounts are now giving me the same issue. Problem is, when I try to add them again now, they don't proceed to the browser window.
I solved 1 issue, got 2 more to solve...