Easiest way to update live app with development app?

I did what I wrote above and after updating any hardcoded URL’s and re-directing stripe web-hooks it seemed to work. All except when I go to reset an users password via the custon login/registration flow. The app crashes with the error:
‘ValueError: dictionary update sequence element #0 has length 3; 2 is required’

When I look at the console I have this error 7 times:
‘Failed to execute ‘postMessage’ on ‘DOMWindow’: The target origin provided (‘https://anvil.works’) does not match the recipient window’s origin (‘https://app.sn4pshot.com’).’

Followed by the same ‘Python exception: ValueError: dictionary update sequence element #0 has length 3; 2 is required’

And: ‘Uncaught (in promise) constructor’ /#reset_password?ema…affe-54833a631d2b:1

and Failed to load resource: the server responded with a status of 404 (Not Found)

My research tells me this is a ‘cross-origin communication issue’ and as it worked just fine before I moved it to my custom domain, I’m thinking maybe just pointing the development app at my custom domain without any intervention from Anvil support could be the root of the issue.

Anyone have an idea on this?

Other than that it appears to be functioning correctly.