Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

Details like websites remembering you (log you in automatically) are stored in a cookie. You need to keep this cookie, possibly by creating a cookie allow exception. *Options/Preferences -> Privacy & Security<br>Cookies and Site Data: Exceptions ---- In case you use "Clear history when Firefox closes" or otherwise clear history. *do not clear the Cookies *do not clear the Site Preferences *Options/Preferences -> Privacy & Security<br>Firefox will: "Use custom settings for history":<br>[X] "Clear history when Firefox closes" -> Settings *https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox *clearing "Site Preferences" clears exceptions for cookies, images, pop-up windows, and software installation and exceptions for passwords and other website specific data *clearing "Cookies" will remove all selected cookies including cookies with an allow exception you may want to keep