Why is my internet really slow when my s8 is connected?

[AC Question]

Hi there,

I have just received my new s8 today and have set it all up. However throughout the night my phone will for example be locked doing nothing but my internst is really slow? Ive turned my phones wifi off and the internet goes super fazt again. Is there some setting or something going on in the background that i dont know about? Please help! My iphone never gave me this problem...