Fabric REST API endpoints for GCC

Thank you for the reply! In the end, we found the following:

• We were initially using PowerShell command (Get-AzAccessToken -ResourceUrl $fabricResourceUrl).Token to request our access token for a personal user.
• We found out that any access token generated in this way on a GCC description does not provide access to any of the Fabric services. Since we are working with a service principal, we tried a different way of getting our access token: 

        $appId = $env:servicePrincipalId 
        $clientSecret = $env:servicePrincipalKey
        $tenantId = $env:tenantId

        $authority = "https://login.microsoftonline.com/${tenantId}/oauth2/v2.0/token"
        # access token
        $body = @{
            client_id = $appId
            scope = "$fabricResourceUrl/.default"
            client_secret = $clientSecret
            grant_type = "client_credentials"
        }
        
        $response = Invoke-RestMethod -Method Post -Uri $authority -ContentType "application/x-www-form-urlencoded" -Body $body
        $fabricToken = $response.access_token

• This new method for token retrieval resolved the issues we were having. We could use exactly the same Fabric endpoints for GCC, but now with a valid access token. I do not have a clear explanation on why this resolves the issue.