Ok, as just exchanged privately:
- your HTTPS POST system information on your localhost were all red, not allowing authorize.net to work properly.
- there was a minor bug in CBSubs 1.0.2 which is now fixed for CBSubs 1.0.3 making the error displayed more explicit.
authorize.net requires HTTP POST to work. Please follow the requirements in red in the CBSubs settings system information and install such needed software, or use it on a real server for tests.
#1276