Unity (2019.1.5f) freezes randomly in editor and sometime when i click play.

Unity freezes randomly in editor and sometime when i click play. I use version 2019.1.5f. I can not reproduce it. But it happens every 1 min to 5 min. Problem seem to have appeared after i updated Firebase.database to dotnet 4 version. I am not sure if it is related. Anyone had similar issues?