S2S REST request not working on some users

So I have a backend for my game and I want to call some S2S requests to get user's data, purchaes and verify purchases. I am using the end point https://graph.oculus.com/${APP_ID}/viewer_purchases to get user's purchases. I provide access_token, user_id, and fields. Just like it mentions in the documention for IAP here https://developers.meta.com/horizon/documentation/native/ps-iap-s2s. The requests are working just fine with some users, but sometimes i enter a user id and get this error:

here is an example of it working:

if i just enter a random user id: (translation: it says thats an invalid user id)

This is not just for this user, it happens for many users. Also it is happing for other requests like https://graph.oculus.com/${USER_ID} to get verified org_id and in consuming and verifying requests. I know that some of these requests dont work for meta test users (users that meta itself uses to test the game) but these users are real players. If anyone has any idea why this is happening please let me know.

Side note: the consume_entitlement request also doesn't work sometimes where it throws a 500 is_transient error with code 2 but it still consumes the purchase correctly. weird...