A PHP Error was encountered

Severity: Notice

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

Filename: controllers/Khachhang.php

Line Number: 21

Backtrace:

File: /home/rroovexqhosting/public_html/finsoft.vn/application/controllers/Khachhang.php
Line: 21
Function: _error_handler

File: /home/rroovexqhosting/public_html/finsoft.vn/index.php
Line: 315
Function: require_once