Wifi not working with some apps

From two days,my wifi started acting weird with some apps...

With instagram i have to close it from the setting if i want the app to work without problems(atleast in the directs)

With Jurassic world the game,the game say that i got a wifi error

Clash Royale loads,but after some minutes in the game,the no wifi sign appears

And...with Pokémon duel,the game load forever

But the strange thing is that with some other apps like youtube and chrome,everything worksn fine without any problems.

So,what i need to do about this?

Im worried that it might be something not good