We have set up a public form via webportal that will collect application payments. We have set up both Authoriz.net and Braintree accounts.  Payments go through using their web tools, but our forms will not.  We get a very generic failure message.

Payment Failed: An error occurred during the payment transaction on <API Name>. Please refer to Authorize.Net with Payment Gateway ID: xxxxxxx

Payment Failed: An error occurred when sending verification to processor on <API Name>. Please refer to Braintree with Merchant ID: xxxxxxxxxxxxxxxx

Both Authorize.net and Braintree support wants to know the response string we are getting back, but so far I have not been able to capture it.  

I have debug level diagnostics enabled in forms, not seeing anything useful in the event viewer. I've also tried HAR trace, maybe just not adept enough to find what I'm looking for there.  Going to set up a packet trace today, I expect the traffic to be encrypted, so I'm not sure how useful it will be. 

I'm no developer, but I can read code OK. Does anyone with experience with either of these integrations have any tips for me?