Why are apps on my phone not working?

[AC Question]

Yesterday I tried accessing Snapchat and it worked fine. I went off of it and a few moments later I tried to go back in and I was logged out. I tried to log back in and it didn't work; all it said was "verifying device" and it didn't proceed further. I tried deleting the app and reinstalling it but it still didn't work. Another issue about Snapchat is that not very often it logs in and what happens is I can't view any stories since they have a rotating circle in the middle of each one of those snaps. If I open one of my messages I cannot reply and even when I try it says message cannot be send please retry so I log out and the same problem happens with the "verifying device" bit. Also my Play Store also does not work, sometimes it has the search bar at the top and a rotating circle in the centre that never disappears meaning that I cannot download any apps. After a while it pops up with text saying "Authentication is required. You need to sign in to your Google Account." I can swipe to the right side and it says I'm logged in. I rooted my phone a while ago but un-rooted it today to see if that was the problem but unfortunately it was not. My phone is a Samsung Galaxy S5 Mini SM-G800F. Thanks