A PHP Error was encountered

Severity: Warning

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

Filename: views/promo_view.php

Line Number: 21

Backtrace:

File: /home/witatour/git/WitaTourOnlineTicketV2/httpdocs/application/views/promo_view.php
Line: 21
Function: _error_handler

File: /home/witatour/git/WitaTourOnlineTicketV2/httpdocs/application/controllers/Promo.php
Line: 57
Function: view

File: /home/witatour/git/WitaTourOnlineTicketV2/httpdocs/index.php
Line: 315
Function: require_once