That app doesn’t appear to have been updated since October 27, 2023. There’s been quite a few changes to Trakt since then. Particularly when it comes to the API which I’d assume is affecting it greatly.
Can’t comment on why you can’t contact the supporter but they do appear to have responded recently to some comments here: https://play.google.com/store/apps/details?id=com.cinetrak.mobile&hl=en-US so I’d try seeking help there in the first instance. Although reading other comments many seem to have abandoned the app.