Impossible to sign in with different user account

DanielNiccoli 

I am afraid the information Eric has provided is correct here. We literally have no control over the authentication process. 

As you can see from the above graph, the Microsoft Login service is self contained and handles Credential collection, validation and error handling and is the same for the entire of Microsoft, you would have the same issue if you went to account.microsoft.com in that it would login with the same profile you have active in edge. I have spoken with the Edge Team about this before and their only suggestion is to use the "Browse as guest" function in Microsoft Edge if you want to login to Microsoft site with any other profile than the one your signed into the browser with. 

We are going to change our connection with the Login service next year but, at this stage, I don't think that's going to have an effect on this behavior, I will of course update if during the course of scoping this change out I find out differently.

Allen