PHP creating new session with each reload

Question

For my website, session management mostly works ok. Sessions are created, saved and used later without problems.

But when the code is using session_start(), it alway

Answer 1

Cookies are only returned to the vhost / path where they were set from.

Since your path is '/', that implies that the pages are not being requested via $domain . "." . $tld;

e.g. user requests page via www.example.com

cookie is set for example.com

user access subsequent page from www.example.com - the cookie is not in scope.

From RFC 2965

x.y.com domain-matches .Y.com but not Y.com.

Actually, if you read on, the spec does say that the user agent should prefix the host with a dot if none is supplied however you getting into the realm where browser behavuiour varies.

If you simply return the cookie with a vhost matching the request it will work as expected.