I don’t know what’s wrong with Barca this season, they’re not at the sort of level you become accustomed to seeing them at. A few of their main players are past their peak so maybe it’s that. They need a big rebuild.
But we can't deny the fact that they haven't lost a single game at home since 13th November 2018, yes, 14 months unbeaten at home! So maybe the problem is not in team or coach but the mentality of players only. Maybe some kind of phobia have developed when they play outside Camp Nou. Or maybe they have bad away tactics like only attack on counters if not playing at Camp Nou. Or maybe Barca players desperately need fans shouting in support. It can be anything but problem is turning serious.
They have to strictly start following same tactical play both at home and away matches. Also Setien has to develop some gameplan to convert possession into chances. Passing balls hundred times in triangle at half way line doesn't win match, midfielders have to pass balls through defensive line so that front 3 can finish. Also, Griezmann needs to adapt to team as soon as possible. It almost become unbearable to see him standing clueless in off-side position when Messi building attacks.