Warning: Undefined variable $expiryDate in C:\Websites\indicat.vn\tools\php\pages\docs\time.check.php on line 8

Fatal error: Uncaught Error: Call to a member function format() on null in C:\Websites\indicat.vn\tools\php\pages\docs\time.check.php:8 Stack trace: #0 C:\Websites\indicat.vn\tools\php\pages\docs\docs.detail.php(2): include() #1 C:\Websites\indicat.vn\tools\php\pages\docs\_docs.php(27): include('...') #2 C:\Websites\indicat.vn\tools\php\index.php(495): include('...') #3 {main} thrown in C:\Websites\indicat.vn\tools\php\pages\docs\time.check.php on line 8