testing recurring contributions -- gone wrong!
The recurring contribution workflow is more complicated than the one-time workflow. For authorize.net, it means that a request for a recurring contribution is sent, but relies on the payment processor to come back with any information about whether the recurring contribution has completed or not (as well as communicating about any future transactions), and typically that will not happen immediately, but at some later time.

I'd guess that you will see pending payments in CiviCRM for these recurring requests, and that for some reason your payment processor account is not configured to properly handle recurring requests (i.e. the callback or IPN isn't firing properly). Perhaps your payment processor account is used for other purposes than online payments?