Same issue using MS Edge from the Activation page of Settings when I click on the 'Learn more' link:
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AADSTS50196: The server terminated an operation because it encountered a client request loop. Please contact your app vendor.
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Request Id: 592dc97d-25d0-423c-b650-7465c6662d00
Correlation Id: 848ab0b1-b4ed-4368-8f01-102451a3090d
Timestamp: 2020-08-08T19:45:14Z
Message: AADSTS50196: The server terminated an operation because it encountered a client request loop. Please contact your app vendor.
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All this time I was getting notified to "UPGRADE" to the NEW Microsoft Edge Browser. I was still using the "LEGACY" version, according to Microsoft. After I installed the "UPGRADE" this ERROR ISSUE went away. So I have to ASSUME it was caused by not upgrading to the newest version of MS Edge.
This fixed my issue.
It may or may not fix your issue(s).
I will keep posting if I get another/repeat error of the AADSTS50196/server terminated an operation ERROR.