I entered my paperless-ngx information, used an API, and clicked login. The next screen is this "Syncing Data" which failed. The only option is to "retry", but since one of the settings was wrong apparently, retry doesn't work. I cannot return to the sign-in screen to adjust my inputs, pushing the "back" button doesn't go anywhere. I would have expected a "back" or "change settings" or something to allow me to correct my inputs instead of being stuck on this sync failed screen.
