If you're being constantly logged out here's how to fix it: Firefox - in the address bar click on the "i" to show site information. Click on the > on top tab for "hfboards.mandatory.com" to show connection detail. Then click on More Information. A window will open with a View Cookies button. Click on that and a window showing your cookies for this site will open. Select Remove All Shown. Now close and restart your browser and log back in with "Stay Logged In" check. This only corrects the issue for me if I reboot the browser. Chrome - in the address bar, click on the "i", then click on cookies. It will open a window showing your cookies here. Repeatedly click the remove button until they're all gone. Reboot chrome. Then log back in with "Stay Logged In" checked.
Now that we have migrated to HTTPS, the address bar should show a lock icon. If you navigate using history or old bookmarks you can be logged out. You should delete and replace them. Make sure this site is permitted to accept cookies. If you get logged out check the address bar. If you don't see the lock icon it's not the https version.