when trying the lead ads testing tool, i am receiving 405 error. the method is POST and I am sure that my callback url is accepting a POST method. can anyone enlighten me to resolve this error?
Another note is that the callback url is a netsuite external suitelet link, so NS gurus might be able to help as well.
See my answer here but basically NetSuite external suitelets require that the User Agent in the request header claims to be a web browser. The best workaround I have found is to use a middleware lambda function to proxy the request.