HTTP Error 400. The size of the request headers is too long

Question

I am trying to do authentication via Azure AD on my Sitecore Instance. I've added my application to the approved list by creating the App Service.

However after the login, the user is redirected to the /Account/ExternalLoginCallback page on the Identity server and it displays the following error message:

HTTP Error 400. The size of the request headers is too long.

Answer 1

We have identified the issue the actual cause is: Cookies that are too big as a part of the authentication request.

As a resolution to the problem: Limit the amount of claims you include in your token. For testing change the groupMembershipClaims: null in the manifest file on the azure ad will allow you to authenticate the request.

Reference: Azure Portal: Bad Request - Request Too Long