Parse error: syntax error, unexpected 'mysqli_connect_error' (T_STRING) webpage error [duplicate]

I have a webpage with mysql but i have error: Parse error: syntax error, unexpected 'mysqli_connect_error' (T_STRING) This is my code:

<?php
//Connect to the database
$conn = mysqli_connect('localhost:8011', 'root', '12345', 'techxx');
//check connection
if(!$conn){
    echo ('Connection error: ' mysqli_connect_error());  
};
?>

Please help!