How to enable cookies in Mozilla Firefox
Mozilla Firefox 31.0
Open Mozilla Firefox if it is not already open.
Go to the Tools menu.
Select the Privacy panel.
Set Firefox will: to Use custom settings for history.
Check mark Accept cookies from sites to enable Cookies, and uncheck it to disable them.
If you are troubleshooting problems with cookies, make sure Accept third party cookies is also not set to Never.
Choose how long cookies are allowed to be stored:
Keep until: they expire: Each cookie will be removed when it reaches its expiration date, which is set by the site that sent the cookie.
Keep until: I close Firefox: The cookies that are stored on your computer will be removed when Firefox is closed.
Keep until: ask me every time: Displays an alert every time a website tries to send a cookie, and asks you whether or not you want to store it.
Click OK to close the Options window.