POST Request Error - 405

Hi guys.
I’m trying to add a form on Jitsi off the welcome page that allows me to send a POST request to an API I’m running to send an SMS message.
It looks like the application denies a method: ‘POST’
Any ideas how to remove this restriction so i can do a POST request?
If you need more info, let me know and i can try to provide it.

POST 405
Uncaught (in promise) SyntaxError: Unexpected token < in JSON at position 0
Promise.then (async)