Web an mobile UIs stuck loading

Configuration Frontend
1

Something changed (probably my fault), but a few weeks ago I went to the web UI and it was stuck on loading forever. Forced refresh, same - weird. Mobile app, same - nothing loads. All of my automations are still working though so I’ve just ignored it.

In an attempt to fix the issue I updated to HA 2026.1 via SSH and the ha command (this is running on a NUC running HAOS) without resolving my issue, so now I’m here.

Looking at the web console, I think this is the issue:
XHR GET https://<host>/unknown/node_modules/@webcomponents/scoped-custom-element-registry/src/scoped-custom-element-registry.ts returns a 404. There are some other errors as well (Failed to execute 'define' on 'CustomElementRegistry'), but I believe they source from this one.

What are my next steps to troubleshoot this? Is this something from HACS I upgraded (or didn’t) and broke things?

2

Having the same issue, and the logs aren’t showing anything helpful. Also having an issue creating/altering automations. I can get to the point where I choose an entity or device, but when I choose an option (“state” for example), the window closes and I’m back to the list of automations.

3

Check this post: Same error