A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_REFERER

Filename: controllers/Api.php

Line Number: 76

Backtrace:

File: /home/howabot/public_html/chatbot/application/controllers/Api.php
Line: 76
Function: _error_handler

File: /home/howabot/public_html/chatbot/index.php
Line: 292
Function: require_once

"Sorry, this URL is not allowed."