Max-age does not work

Question

I have PHP code that implements the max-age header. I hosted the same code on different servers on different web hosts. However, I see that max age works on one, but doesn't work on the other. I can’t understand what the problem is because the code is the same. Does the heading for maximum age depend on anything else?

By the way, the following code I used.

header('Cache-Control: max-age=60, public'); header('Content-type: text/html'); echo date("F j, Y - H:i:s");