Well I'm almost certain there was a lot of factors that contributed to your bad season, but strained relationships between manager and players when things are going desperately wrong is kind of normal.
I mean I'm sure relationship between the two was not strained season before when Hazard had his best ever season and you won the title! That's modern game for you though, as weird as it sounds, success kind of drives that relationship with a manager and player. If you're playing well you love the manager and think he is doing everything right, if you are not playing well and team is doing badly you suddenly start to doubt all he managed to achieve with you just a season ago. Both individually and collectively speaking.