Pro API for Remote Operations - How to troubleshoot issues

Apologies if this is more of a Wordpress/PHP related problem.

I’m trying to utilise the Pro API for remote operations but can’t seem to get any feedback in the logs as to what issue I’m running into.

I’m using the API from a custom REST endpoint.
I’m on the same domain.
I load the file that contains the Pro API functions using require_once FILE_PATH.
I’m trying to test a very basic implementation of one of the provided scripts but my function returns null and no error is returned. I have WP_DEBUG enabled, and nothing is caught in the Wordpress error logs.

I’m also relatively new to PHP and Wordpress and couldn’t find much about how other people have implemented these scripts. Is there anything else I could do to try to troubleshoot this issue?

You can turn on s2member logging. See

You can also test your API calls using a free tool like Postman for easier debugging

Thanks for the suggestions Tim. I was able to expose a server configuration issue by running the code from a child theme and get this working.