I'm currently making a POST to https://api.appstoreconnect.apple.com/v1/betaTesters with all the correct credentials and getting a code 405 METHOD_NOT_ALLOWED.
As far as I know, I am in fact making a POST request as noted in the documentation: https://developer.apple.com/documentation/appstoreconnectapi/create_a_beta_tester#see-also
Any one else seeing this, please help.
does it have anything to do with the 2FA introduced for app store connect?
I was actually to do with the fact that I added "scope" to my token request. Apparently it worked a little too well! :D
See under "Scope" heading
https://developer.apple.com/documentation/appstoreconnectapi/generating_tokens_for_api_requests
Removing it fixed my problem!