Mozilla Firefox

1. Click on the Tools-menu in Mozilla
2. Click on the Options... item in the menu - a new window opens
3. Click on the Privacy selection in the left part of the window. (See image below)
4. Expand the Cookies section.
5. Check the Enable cookies and Accept cookies normally checkboxes.
6. Save changes by clicking Ok and go to one of the configuration pages again

Older Mozilla versions

1. Click on the Edit-menu in Mozilla
2. Click on the Preferences... item in the menu - a new window opens
3. Expand the Privacy & Security selection in the left part of the window.
4. Click on the Cookies selection.
5. Check the Enable all cookies checkbox.
6. Save changes by clicking Ok and go to one of the configuration pages again