Error Code 403:Forbidden

[angsumankar]

I have developed an app using Spotify WebAPI.

For submitting request for quota extension, I’m preparing a Spotify test account. This test account is a premium account as my service uses some of the APIs which are required users to be a premium user.

Even after being premium user, I’m receiving error code 403:Forbidden when using this test account for testing my app. It is coming randomly sometimes for reading current player context or sometimes for reading current track details.
This test account profile name and email address has the word “Test” in it. 
When I test the app using my personal accounts then it is working completely fine. Please note that from authentication to authorisation everything is same for all user accounts.

Is there any kind of restrictions present around word “Test” for using in user name or email id which Spotify might be using to filter accounts for stopping misuse of their systems. 

[Ximzend]

Have you already added the information of the test account at the dashboard of your app, as you can read here: https://developer.spotify.com/documentation/web-api/concepts/quota-modes

[angsumankar]

Yes. Test user information is already added into the allowed list of users for the app.