Error 'AADSTS900561: The endpoint only accepts POST requests. Received a GET request.' on opening site with SharePoint Designer

Question

When I try to open a SharePoint online site (on a specific tennant, on most tennants I do not get this error!) with SharePoint Designer 2013 I receive the following error, after passing my username and password:

Opening the URL (https://login.microsoftonline.com/xxxx/login) from the above error gives the following:

After the error the login proces stops.

I already added the sites https://*.microsoftonline.com and https://microsoftazuread-sso.com to the trusted sites with no results.

What to do?

Answer 1

Hi @Walter Branten,

Since the error only occurs on one tennant. Please go to the admin center to check the user.

1. Please check if you have blocked sign-in

1. Check if the user have enough permission to the site

1. Reset the password

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