How I followed all methods and failed …
I create a collection at https://addons.mozilla.org/en-US/firefox/collections/
Then copied collection user ID and collection name and enter it in the custom addon collection field.
Here’s the link to the latest builds.it’s a build on their CI server.
https://firefox-ci-tc.services.mozilla.com/tasks/index/mobile.v2.fenix.nightly.latest
I tried 90 version also but failed to addon .
Installed from Google Play Store again failed .
https://github.com/mozilla-mobile/fenix/issues/15529 ,
And now I’m getting a popup that says add-ons are failing to load. I can’t change settings on any addon, which with NoScript means new sites don’t work because I can’t white list things. Anyone else getting this?
EDIT: Looks like I’m not the only one. And yes, disabling custom add-ons fixed it, so if anyone does have this issue after trying it out, delete that info, restart the app, and it should work again.