Can't Login to Yahoo Mail on Firefoxby Kevin Lee
Computers, browsers and the Internet must work together successfully as a team if you wish to log in to password-protected sites such as Yahoo Mail. If your Internet connection is working and you're having problems accessing your Yahoo email using Firefox, Mozilla lists several solutions you can try to gain access your Yahoo email.
Narrow Down the Problem
Use a process of elimination to determine if Firefox is preventing you from logging in to Yahoo. You can do that by trying to sign in to Yahoo Email with a different Web browser, such as Internet Explorer. If login fails on that browser too, Yahoo may be experiencing a temporary site problem. Wait a while and try to log in to your account again. On the other hand, if you log in successfully using another browser, you'll need to try other solutions.
Check Your Password
If you can't sign in to your Yahoo Mail account, ensure that you're using the correct password and username. Firefox could be putting an old password in the "Password" text box if you've set up Firefox so that it fills in form values automatically. Because the browser masks the password, you cannot see it when Firefox puts it in the Password text box. Instead of letting the browser log you in automatically, type your password manually in the “Password” text box and click “Sign In.” This problem can occur if you change your password frequently and Firefox remembers them all.
Clear Your Cookies and Temporary Files
Yahoo and other websites use tiny bits of information called cookies to customize your browsing experience. Firefox also stores temporary data in its browser cache. Clear the cache and cookies and you may be able to log into Yahoo Mail. Perform this task by clicking your "Firefox" button followed by "History" and selecting "Clear Recent History." Click the "Time Range to Clear" drop-down menu and then click "Everything." You'll see an arrow next to "Details" that displays a list of items when you click the arrow. Click that arrow, put check marks in the "Cookies" and "Cache" check boxes, and then click "Clear Now." Return to the Yahoo page and try to log in again. Clearing your cookies and cache often resolves website problems.
Enable Your Cookies
Ensure that Firefox's cookies are enabled. As Yahoo notes, you may not be able to sign in to some Yahoo products if they are disabled. Enable cookies by clicking your "Firefox" button and selecting "Options" to open the Options dialog window. Click the "Privacy" tab, click the "Firefox Will" drop-down menu and select "Use Custom Settings for History." If you don't see a check mark in the "Except Cookies From Sites" check box, put a check mark in the check box. Click the "Accept Third-party Cookies" drop-down menu and select "Always" if that value is not selected. Click "OK" and try to log in to your Yahoo email account again.
If Your Firefox Button Is Missing
Firefox gives people the option to display the browser's menu toolbar. If yours is visible, you will not see an orange Firefox button. You can still open the Options dialog window by clicking "Tools" followed by "Options." If your menu toolbar is visible, you can also simply click "History" if you need to clear your browser's cookies and cache as described previously.