GMAIL Calendar Feature Stopped Working?

Windows 10, version 21H1. Brave, Firefox and Chrome all up to date. Same results when I try all three and on two different computers. No difference if VPN is on or off. This has been going on for about 10 days now. I click on a calendar event to "view all event details":



And I get this page:



I did make a change recently but I don't know if it is related or not:

I came across this URL "How to Get rid of GMAIL Ads" and followed the instructions...



Head to Gmail in your browser and click Settings (cog wheel icon) in the top-right corner.
Click See all settings at the top of the panel that appears.
Go to Labels, then scroll down to Categories.
Under Show in message list, click hide on Social, Updates, Forums, and Promotions

...if changing these settings did something I do not recall what they were before. HOWEVER using different GMAIL accounts and on the other computer the setting looks different but I still get directed to the error page above.

I can go into Calendar and search for the event and I see it and I can click on the event and edit it if I want but the feature from my INBOX is no longer working. Insight welcome. TIA.

Perfect description. I have had the same problem for about 2 weeks now. I am running Windows 10, 64bit. Using Outlook 2019 desktop.