Hello @harry88
- What type of ‘app’ are you creating?
- What development language / framework / libraries does this app use?
- Which specific API endpoint are you accessing to get those custom fields (I don’t know of any endpoints that end with the word ‘fields’)
- What is the actual request being sent to that endpoint with what parameters?
- What are the scopes being using with that request to that endpoint?
- What documentation are you referencing and what tests have you done outside your code using your API test tool?
Refer to the How to ask a good question thread on the minimum amount of information that would be required to be able to assist with your problem.