Wefwef recently bugged out on me where I couldn't log into any instance or view any posts. Is this the same issue you're having or no? I had to delete the PWA, then navigate to my browser and delete all of the saved site settings for wefwef (or Voyager now). Then I was finally able to load the site again and log in.

What I occasionally have issues with in Voyager/wefwef is that I randomly cannot post comments because it asks me to select a language. My language is set to English in my profile, and no amount of fiddling with the setting seems to make the app function. Other times it's totally fine so I don't get it.