Outlook 2016 fails to connect to gmail

I recently noticed that Outlook on Windows 10 on the desktop machine (amber) had stopped connecting to my gmail account. I'm not sure how long that had been the case. The gmail connection from Outlook on the Windows 10 laptop was working just fine, so some environmental problem on amber seemed to be the likeliest cause.

First, tried the obvious of deleting the gmail account in Outlook and re-creating it. Outlook 2016 can handle OAUTH2, so handed off to Google for the username and password. But every time, once Microsoft had been granted access to email, Outlook reported it could not connect.

Then, tried the usual option of re-installing Outlook. No, that didn't work. Next, went through the registry, deleting anything that was obviously noted as Outlook and related to my gmail email address. Nope, no change.

I search the web for potential solutions, but it wasn't until I used the query "Outlook" and "credentials" in the same query that I was pointed at the certificate store on Windows. So, I used the Credential Manager (via the Control Panel) to delete all OAUTH credentials owned by Outlook (there were four).

Restarted Outlook and tried to create the gmail account again. This time, after granting access via Google, Outlook spun its wheels for a couple of minutes. Then it said: "Something went wrong". However, once I hit the option to Retry, connection was established.