Dogs not attacking any mob

I tamed a wolf on survival mode and had it for a while it was attacking mobs and then suddenly never attacked another mob. I tired hitting the mobs making my wolf sit and stand and then hit the mobs but nothing my wolf wont attack any mobs at sometimes it can even be unresponsive. Like sometimes when I make my wolf stand up to follow me it will just sit there and wont ever even teleport to me.