Unable to access my application API

I have secured my application using Cloudflare Access. Pages are working however the POST API calls are responding empty (call is not reaching to the server).

I have come across a Cloudflare support page that suggests how to deal with Application API using page rules. The problem is that my APIs are not categorised under a pattern i.e. https://example.com/api/*. For example

Page: https://example.com/user-details.html
GET https://example.com/user-details/getdata
POST https://example.com/user-details/update

Please suggest.

Best Regards.