As per the news from Express UK on November 30, “Microsoft Teams" is undergoing a big change and they will stop operating their web based versions on Internet Explorer 11 starting from November 30.

If you're an Internet Explorer fan you'll have to switch to Microsoft Edge to use Teams in a browser. Microsoft has announced this big "Microsoft Teams" change earlier this year, and it appears to all be part of a push to move Internet Explorer 11 users onto Edge.

Besides IE11 losing Microsoft Teams support at the end of November, IE11 will also no longer be able to access Microsoft 365 services in the future. On August 17 2021 the remaining Microsoft 365 services will stop working with Internet Explorer 11. These changes were announced in one of Microsoft’s blogposts and you can check it by clicking the link.