Hi omid_student,

It will depend on the website where an account will stay logged in. However to store logins you can try the password manager: Password manager - Remember, delete, change and import saved passwords in Firefox

There are some web pages that do not allow browsers to record or fill in the log-in information. But if you go to the Mozilla Add-ons Web Page {web link} (There’s a lot of good stuff here) you can find several add-ons that can override this, and give you better control of your password information. You can also try a Form Filling add-on.

Details like websites remembering you (log you in automatically) are stored in a cookie.

• Create a cookie 'allow' exception to keep such cookies, especially in case of secure websites and when cookies expire when Firefox is closed.
• Firefox > Preferences > Privacy > "Use custom settings for history" > Cookies: Exceptions

Clear the cache and remove cookies only from websites that cause problems.

"Clear the Cache":

• Firefox > Preferences > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox > Preferences > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Thank you my friends. I remove cookie of website that not login and it's work