@LoudLemur couple of points raised :
cloudron only allows one assigned port like 1965 to one app. Once done, it's occupied/blocked. You need to uninstall the deployed app to clear it.
From CLI :
cloudron uninstall --app app.domain.tld
Or from the app dashboard 'Uninstall' option
you gave a code shot which mentions "agateplus.example.com". I'm guessing you obscure the actual app URL which is fine and wise. But it also refers to a docker registry. That's an example.
Just to clarify, did you build the app and deploy it to your registry ?
That's necessary for custom apps, and that's probably why the 'unable to pull' message was generated.
I am still tweaking the handling of multiple deployments. Cloudron supports it, and agateplus too, but I am resolving some content caching issues.
Advice for now is stick to one deployment until I solve the cache issue.