A PHP Error was encountered

Severity: 8192

Message: strtolower(): Passing null to parameter #1 ($string) of type string is deprecated

Filename: controllers/Member.php

Line Number: 144

Backtrace:

File: /www/wwwroot/qhtravel.crowntw.com/application/controllers/Member.php
Line: 144
Function: strtolower

File: /www/wwwroot/qhtravel.crowntw.com/application/core/MY_Controller.php
Line: 51
Function: register

File: /www/wwwroot/qhtravel.crowntw.com/index.php
Line: 320
Function: require_once