Ok. Now we now it’s not trakt, install and reinstall, and not authorisation issue.
But indeed it could be the app itself, when I searched the web for Film Plus Apk I came across few websites with different versions eg 1.4.2, 1.4.3, and even version 2. Some are compatible with all Android devices, and other with android tv.
It could be the version you’re using, and as you mentioned that is compatible with android tv, and not with android os. So the best thing to do is indeed waiting for answer from developers.
Note: Everything I searched about Film Plus was advised to authorized with RD, and not with AD.
According to other users not only with film plus but other APK’S as well. They experiencing to many issues with AD. After replacing AD with RD they didn’t have any issues anymore with eg authorization, links.