After the installation process I receive a notification
"Warning: The home dir /var/lib/bitcoin you specified can't be accessed: No such file or directory
Adding system user `bitcoin' (UID 113) ...
Adding new group `bitcoin' (GID 122) ...
Adding new user `bitcoin' (UID 113) with group `bitcoin' ...
Not creating home directory `/var/lib/bitcoin'.
bitcoind.service is a disabled or a static unit, not starting it. "
I started opening bitcoin-qt unsuccessfully
" sudo bitcoin-qt
QXcbConnection: Could not connect to display
Aborted (core dumped)"
I'm using Ubuntu 16.04
user sudo but not root
Is there any way to solve this problem?