Get Token Access for PBI API - Credentials issue

Hello, 

Few months ago I built a Power BI to follow my admin activities and it was working fine at the time.

However I tried to refresh it today and it failed because of Credentials issue with the function that I used to get a Bearer token. 

I used to set the Credentials to Anonymous but it's not working anymore and I do not see whichever other type I can use.

Do you have an idea to solve this problem ? 

Here's my function code : 

= () =>
let
    url = "https://login.microsoftonline.com/common/oauth2/token",
    postBody = [
        grant_type = "password", 
        username = "myUserName",
        password = "myPassword",
        client_id = "myClientID",
        client_secret = "myClientSecret",
        resource = "https://analysis.windows.net/powerbi/api"
        ],
    response = Json.Document(Web.Contents(url,
        [
            Content = Text.ToBinary(Uri.BuildQueryString(postBody))
        ])),
 access_token = response[access_token]
in
access_token

And the error message : 

Thanks a lot for your input !