To my knowledge that endpoint shouldn’t/deosnt’ have rate limiting.
So check the
- HTTP code
- the actual response message
- headers
Also note you only need to refresh a user token when you need to use a token, so auto refreshing it on the four hourly~ish schedule might be overkill.
But I suppose it does depend how many user tokens your service is trying to refresh, it should onlty have the broadcasters token for sub read/channel update/etc.