Is there somebody who can help me?
LE 9.2.8 is old now so our first response is going to be "Please test a current release" to eliminate all the fixes and updates that were made since (there's been a few). I appreciate there are possible reasons for remaining on LE9.2 with an RPi3, but even if there's an issue and that can be pinpointed (sharing some debug logs would be a good first step) there's not going to be any fixes in that release, it's a long dead codebase.
NB: Tvheadend has evolved too. How old?