Most sites that you log in to do not work correctly without cookies. The cookies connect your request to your open session. Without the cookies, your request could be from anyone anywhere...

To check your permissions, while viewing any page on google.com, you can open the Page Info dialog to the Permissions tab. Three ways to do that:

• Click the padlock icon in the address bar > More Information > Permissions
• right-click the page > View Page Info > Permissions
• tap the Alt key > Tools menu > Page Info > Permissions

There you can check whether you let Google "Set Cookies" (either Allow or Allow for Session) and "Maintain Offline Storage" (Allow). I think you need both of those for Gmail to work correctly.

The forum software detected your Firefox as version 19. Is that correct?

Version 19 is not secure; Mozilla discloses security flaws after each new release. Is something holding you back from upgrading to Firefox 24? Please let us know so we can suggest solutions or workarounds.

Or if you're ready to upgrade, you can use Help > About Firefox > Check for Updates to get it.

If Help > About Firefox shows Firefox 24.0, you may need to clear the preference that is misreporting your version number. See: How to reset the default user agent on Firefox.

What are your current cookie settings?

To see all History and Cookie settings, choose:

• Tools > Options > Privacy > Firefox will: "Use custom settings for history"

• https://support.mozilla.org/kb/Options+window+-+Privacy+panel

There are also extensions that can block cookies and other files (data), so you can check that as well.

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