ERROR: SQLSTATE[HY000] [2002] No such file or directory - When pushing to server

Question

I have my website working fine on my local machine, but have just ssh'd into my server and cloned my git repository but getting this:

ERROR: SQLSTATE[HY000] [2002] No such file or directory

And then an error with the connection variable which is set in a try catch.

All my database credentials are correct, 100% and I have logged into the server.

Any help?

Edit:

$host = '127.0.0.1';
$dbname = 'doseofst_every_hour';
$username = 'doseofst_craig';
$password = 'password';

try {
  $conn = new PDO(
    "mysql:host = $host;dbname=$dbname",
    $username,
    $password
  );
  // show errors
  $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

} catch(PDOException $e) {
  echo 'ERROR: ' . $e->getMessage();
}