A PHP Error was encountered

Severity: 8192

Message: md5(): Passing null to parameter #1 ($string) of type string is deprecated

Filename: controllers/Auth.php

Line Number: 26

Backtrace:

File: /home/edoc/public_html/application/controllers/Auth.php
Line: 26
Function: md5

File: /home/edoc/public_html/index.php
Line: 308
Function: require_once