I have a service developed for SONOS which is already deployed. Sometimes I need to test it against my local copy of the API. I connected my SONOS player to my local API using the form at <sonos.ip>:1400/customsd.htm, and it worked fine for a couple years. But I recently deleted that service from my app so that I could recreate it, and now it won't recreate. The form still gives me a "Success!" message, but no combination of settings I've tried, on any SID, has been able to make the new service show up in my app.
I've already deleted and reinstalled the app and done a full factory reset on the SONOS player, and it just won't create a new service (but it always tells me, "Success!").
So I was being dumb. I forgot that, in addition to creating the service at customsd.htm, you actually have to add a new service in the app, scroll through the list and find the new service you just created. Don't I feel foolish.