Confused

So i was on tiktok the other day and went on my friends profile and it said he had no followers no posts no reposts no nothing obviously i got confused so i checked a bigger tiktokers profile and it had exactly the same problem so i got rid of the app and installed it again and now everytime i try and login it says “unable to authorise” or “check your internet connection” even though im connected to the internet and i cannot access either of my accounts. Please someone tell me why