adduser directory problem

Hello all, i am running an ubuntu 16 system on a VPS and i just started learning about this.
if i add a user with adduser username the system adds the user and the homedirectory /home/username
when i login from root as user it shows : username@servername
so far so good.
whoami gives: username
when i make pwd command it should show me : home/username/ because i am looged in as the user.
but pwd give me /root so i am still in the root directory as a user...

how can i solve this or what did i make wrong because when i login as a user i should only see the users directory /home/user and not the root directory.

maybe someone can help me please?

thanks a lot