I found my problem, I had inadvertantly made a change that left the authentication token null and without that value the web service is disabled. I never found a message in a log, I just started working back through the pass from the beginning and found the error. Thank you to those that viewed the question.

Looking back, on 2/19 I was returning a 405 status on a DELETE. Is it possible that Apple disabled something because the DELETE was not handled correctly? I'm not sure if/where I would find that on the developer web site.

After some further investigation, the notification controls vanished from the pass before the push notification attempts yesterday. So, we had working passes installed on two devices. Both devices registered their pass and accepted notification to refresh their pass. Then, with no change to the pass code, the pass controls to control notification vanished. I reloaded a new pass and it does not attempt to register (no events at the web service proxy). Any thoughts on how to find the error?