Forbidden error by creating chat thread

Question

Hi,

want to implement teams chat via ACS. Calling and chatting is initiated from angular application. Participants are AAD users having teams license.

Access token part is implemented:

List<string> scopes = new() {    
"https://auth.msft.communication.azure.com/Teams.ManageCalls",  
"https://auth.msft.communication.azure.com/Teams.ManageChats",    
"https://graph.microsoft.com/Chat.Create",
"https://graph.microsoft.com/Chat.ReadWrite.All",
"https://graph.microsoft.com/Chat.ReadWrite"
};
    // Create an instance of PublicClientApplication
    var aadClient = PublicClientApplicationBuilder
                    .Create(appId)
                    .WithAuthority(authority)
                    .WithRedirectUri(redirectUri)
                    .Build();
    // Retrieve the AAD token and object ID of a Teams 
    var result = await aadClient.AcquireTokenByUsernamePassword(scopes, user, password).ExecuteAsync();

Azure Communication service has assigned all the permissions listed in the scopes above. All the permissions are granted.

When trying to create thread with generated ACS token by:

POST https://xxx.communication.azure.com/chat/threads?api-version=2024-03-07

Getting following response:

{ "CommunicationError": { "Code": "Forbidden", "Details": [] } }

Thank you for any help.