Line Graph not loading in Firefox b/c of ServiceWorker error

Hi, I’m having this problem for a couple of weeks now: When I open my Loveloace dashboard in Firefox 91, some or all line graphs do not load, only the loading animation is displayed. I haven’t had this problem in other browsers (so far!), but don’t want to have a second browser open just for HA :wink:

The cards all correctly show the current sensor values, but loading historical data seems to be interrupted. I’m accessing the HA instance on my NAS via the Nabu Casa URL.

In my browser console I can see errors of this kind:

Failed to load ‘https://***’. A ServiceWorker passed an Error Response to FetchEvent.respondWith(). This typically means the ServiceWorker performed an invalid fetch() call.

and NS_ERROR_INTERCEPTION_FAILED in the networking tab for these requests.

I’ve already tried several things:

  • cleared the browser cache, cookies, local storage etc.
  • deleted my home-assistant_v2.db as per recommendation in other topics
  • disabled browser extensions.

but with no success. I’m running out of ideas now, and I don’t have much knowledge about Service Workers.

Anyone with ideas that could help?

Turn off enhanced tracking protection for the site (shield icon in the URL address bar).

Thanks for the suggestion! I double-checked, it’s already disabled, so unfortunately it does not solve the issue.

Things seem to get worse instead of better. I frequently get the error “Unable to connect to Home Assistant.” when I try to load the UI in Firefox. Only after multiple reloads (either by clicking RETRY or reloading the whole page) I get to my Lovelace dashboard, but still without most of the line graphs. I’m at a loss here.


This has never happened in Chromium so far.

I’m on 2021.9.5 now, and that problem does not seem to occur anymore.
Not exactly sure why, but it seems to be fixed.