A PHP Error was encountered

Severity: Notice

Message: Trying to access array offset on value of type null

Filename: controllers/Article.php

Line Number: 131

Backtrace:

File: /opt/apache/www/onlinebutterfly.education/application/controllers/Article.php
Line: 131
Function: _error_handler

File: /opt/apache/www/onlinebutterfly.education/index.php
Line: 292
Function: require_once