Confusing PDO-only problem : Can't connect through socket/Access denied/Can't connect to server (shared host)

Question

So the problem changed from what it was, i\'ll leave the original question below to prevent bad reviews on answers like I had after someone editing his question I answered :

Answer 1

Is your server running with SeLinux enabled (enforcing)? If it is, try running as root:

# setsebool -P httpd_can_network_connect on