It sounds like you likely cleared your browser cookies. Cookies are used to keep you logged into a website so that, if you leave the website and come back, it remembers that you are logged in.

You will need to log back into the website with your username and password to regain access to it.

Could you clarify the problem:

(A) Site says your username + password combination is not correct

(B) Site logs you in, but keeps sending you back to the login form over and over

(C) Site logs you in, everything is normal until you close Firefox and re-open it, then you need to log in again

Is it possible any cookie or other privacy settings were changed around the same time that you emptied the cached files?

Sorry for not being clear. I can log in but once I go out of that specific site, I need to log all the way back in again. For example, email. There is an option to stay logged in for two weeks (ATT email) I can stay logged in with Edge but not with Firefox. It keeps asking me to put in both the user name and password. I didn't change any settings.

Its most likely option B that you provided

Let's say you are viewing your email in a tab, and you use a bookmark to go to a different site in that tab, then you click the Back button to return to email. Does it make it you log in again?

If that's okay, what about when email is open in one tab, you open a new tab in the window and close the email tab. Then use "Undo Close Tab" to restore the email tab, either by right-clicking the current tab and choosing Undo Close Tab or by pressing the Ctrl+Shift+t shortcut. When the tab is restored, do you need to log in again?

The next level would be closing the window by closing all tabs in the window, and so on. At what point are you unable to stay logged in and you need to log in again?

If I go to another web site with another tab (I have never used a Bookmark, I always just open another tab) I can return to the email or whatever site I was in. The problem is when I leave the internet and then re open it. It does work in Edge but not FireFox.

Make sure you do not run Firefox in permanent Private Browsing mode (Always use Private Browsing mode; Never Remember History).

• https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history
• https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing

• Options/Preferences -> Privacy & Security
  Firefox will: "Use custom settings for history"
• remove checkmark: [ ] "Always use Private Browsing mode"

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
  Firefox will: "Use custom settings for history":
  [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 exception for password and other website specific data
• clearing "Cookies" will remove all selected cookies including cookies with an allow exception you may want to keep

To Cor El, your answer was helpful but I had some more questions so I didn't know if I clicked on "solved the problem" it would allow me to ask further questions. When I checked not to clear the cookies, it now allows me to go to web sites automatically. But I always had delete cookies prior to last Friday and it had been working. Won't cookies eventually "clog" up the cache or some other section in my CPU?

You can let the cookies expire when Firefox is closed to make them session cookies instead of using "Clear history when Firefox closes" to clear all cookies including cookies with an allow exception you may want to keep.

• Options/Preferences -> Privacy & Security
  Cookies and Site Data: [ ] "Delete cookies and site data when Firefox is closed"

You can create a cookie allow exception and use "Delete cookies and site data when Firefox is closed" to let cookies without allow exception expire when Firefox is closed.

I unchecked "delete cookies and site data when Firefox is closed" and it works but when I went back in and re checked this box, the problem returned. I don't understand how to create a "cookie exception" Would setting up a cookie exception allow access to web sites without constantly re entering a user and password? If so, please tell me how to create a cookie exception

...please tell me how to create a cookie exception

The easiest way to make an exception for a site is to use the Page Info dialog. While you are on the relevant page, you can call that up using either:

• Ctrl+i (for Mac, Command+i)
• right-click a blank area of the page > View Page Info
• (menu bar) Tools > Page Info

When the dialog comes up, click the Permission icon at the top to show that panel.

Cookies - Scroll down to "Set Cookies" and uncheck the "Use default" box, and then select Allow to let the site set persistent cookies.

Note: if the site updates a session cookie, then it won't carry over the next session. You can clear the site's cookies after making the exception and then log in to make sure it sets a persistent cookie.

To remove the site's existing cookies: While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that.

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Hopefully after all that, you'll be good to go.