Warning: Trying to access array offset on false in D:\wwwroot\mtbook\web\html.php on line 50

Fatal error: Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array, null given in D:\wwwroot\mtbook\web\html.php:50 Stack trace: #0 D:\wwwroot\mtbook\web\html.php(50): in_array('102127', NULL) #1 {main} thrown in D:\wwwroot\mtbook\web\html.php on line 50