Websites remembering you and automatically log you on is stored in a cookie.

You need to keep the cookies as well, so maybe trey to add an allow exception and make sure not to clear the cookies via Clear Recent History or otherwise.

In case you are using "Clear history when Firefox closes":

• do not clear Cookies
• do not clear Site Preferences

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [X] Clear history when Firefox closes > Settings
• https://support.mozilla.org/kb/Clear+Recent+History

Note that clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, and passwords.

Clearing cookies will remove all specified (selected) cookies including cookies that have an allow exception and cookies from plugins.

You can inspect and manage the permissions for all domains on the about:permissions page.

• https://support.mozilla.org/kb/how-do-i-manage-website-permissions

Do not use Clear Recent History to clear the "Site Preferences" and the "Cookies" as this doesn't take exceptions into account, but removes all specified data.

The clear history settings were correct. This happens only on my laptop and started with the last Firefox update, 20.0.1. My desktop works fine.

If you right-click a page on the site > View Page Info > Permissions tab

Is Set Cookies set to Allow?

Yes it is. I verified that I set the clear on exit variables to not clear cookies or active logins

Are you clearing any data when you close Firefox?

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": Clear history when Firefox closes
• https://support.mozilla.org/kb/Clear+Recent+History

Yes. I have set it to clear Browsing, Download, Form& Search, and the cache.

Does it have any effect if you do not use Clear Recent History and remove the check-mark?

• Tools > Options > Privacy > Firefox will: "Use custom settings for history": [] Clear history when Firefox closes

No and now my desktop is doing the same thing

Do you have security software (firewall, anti-virus) that may be blocking cookies?

Check the date and time in the clock on your computer: (double) click the clock icon on the Windows Taskbar.

• https://support.mozilla.org/kb/Secure+Connection+Failed

Yes and I just added my ISP home page to the trusted list

Does anyone else have this issue?

Just to clarify, when you say your ISP, do you mean the Yahoo! site?

Yahoo seems to do some security checks that you can fail if your connection has changed in some manner since the cookie was set or last validated, and they require you to log in again. In the past, people have worked around this by changing their connection setting to No Proxy here:

orange Firefox button (or Tools menu) > Options > Advanced > Network mini-tab > "Settings" button

If you use any kind of anonymizing software or service that might change the IP address you use to connect to Yahoo, this might also be a factor. (Note that Firefox's private browsing feature doesn't do that.)

I changed the setting. I will watch it for a day before I will know if it solves the problem. The first time, it did work but I have had it work a single time before.

Thanks

This seems to have worked on one computer but not the other. I will keep monitoring

We are back to ground zero. It is signing me out on both computers. Could it be my ISP?

It could be your ISP if your IP address changes frequently.

You might also check whether you run any external cleaning software that removes cookies (some security suites, privacy software, and cleaning utilities can do that).

I am not running any external cleaning software on a daily basis so it may be the ISP

Thanks

The problem cleared up for a while but came back after a firefox crash.

I have not heard anything for a month. The problem still exists even after the update to version 21.