MIT App Inventor doesn't work properly, "Ooops! We tripped on a Bug!"

I have used scratch of MIT and HTML and javascript
MIT app inventor doesn't work properly
When i go to the coding and the screen it works but after sometime when i click button for adding blocks or code, it says error. It not only happens today. It also happen before 3 months when i tried to join and i tried today then also it failed.
Google Chrome 84.0 and Windows NT 6.1 or Windows 7 Professional Edition

And what error would that be?

Ooops! We tripped on a Bug!
Please help us by telling us what you were doing at the time this happend. We have already included some technical data with this report. If you do not submit this report, nothing will be reported to us. If you do submit a report, your comments along with the technical data will be sent to us.

Thank you for your help in making MIT App Inventor better!

Technical Data to be Submitted:

notes =
foundIn =
faultData =
projectId = -1