hello, if you're running in private browsing mode then this would be the expected behaviour (no idea why it would have behaved differently before) as your login information is stored in cookies which get purged at the end of a private session.

Im not talking about logout at the end of the session, I'm talking about logout in 1 minute after login, without closing Firefox. Maybe my first post not clarified this enough.

could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

I'm running polish version of Firefox is it ok to post it anyway? Meanwhile, I tried to find more answers on that same matter, but nothing is working. Also tried to turn Firefox without any add ons, problem still exist.

By the time I read down, I forgot you already tried these. Never mind!

Firefox should keep your cookies in private windows to share among the tabs there. Unless the cookies are damaged, they should work same as before. You can clear the cookies for problem sites individually using the Page Info dialog:

While viewing a page on the site, try either:

• right-click and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"
• click the padlock or globe icon in the address bar > More Information > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try logging in again and see whether the login remains valid.

Some sites are sensitive to your connection settings, so for those sites, you may not be able to use "Auto-detect" in the following dialog:

"3-bar" menu button (or Tools menu) > Options > Advanced

On the Network mini-tab, click the "Settings" button. The default of "Use system proxy settings" should piggyback on your Windows/IE LAN setting. You also could try "No proxy".

Did you check your security software to make sure that it isn't blocking the cookies?

Create a new profile as a test to check if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox