PHP Session Variable from subdomain to main domain

Question

i Have setup 2 domains/sites in the ISPConfig on amazon Web server EC2 instance,

i have a domain named app.example.com and the other is https://www.example.com Both dom

Answer 1

I would like to make a little correction,

Bad: setcookie ("PassMySessionName", $_SESSION['user_name'], time() - 3600, "/", "example.com");

Correct: setcookie ("PassMySessionName", $_SESSION['user_name'], time() + 3600, "/", "example.com");