My php project work properly on local server but does not work properly when I put it online on the web server, WHY?

I'm working on a php project.. And I started building the admin login system and have already finished it and it works properly on my machine (local server) where I'm developing the project.. But when I moved it to a (web server) it didn't work properly as it was working on (local server).

the problem that showed up is that when the admin get authentication to log in to the admin area, once he clicks any link in the page or even he reloads the page that page disappear and the login page appear again which mean the adm开发者_如何学Goin forced to log out even he didn't.

Sounds like it might be a cookie or session issue depending on how you are handling your logins.

Could be anything... different path structure (live site is in root, local site in subpath of root), hard-coded link, bad info in DB, bad .htaccess.

I had such a problem and it's reason was that the database details were not changed when I deployed the application on web host. It still had my local database credentials instead of the database details of the web host :P