https://support.mozilla.org/en-US/kb/websites-say-cookies-are-blocked-unblock-them

If you read my post, I have tried all those suggestions. None of them worked. Thank you for your contribution/suggestion though. I appreciate it.

It sounds as though it's not a problem with cookie settings or cookie data.

Firefox's cookie settings also control access to "local storage" sometimes called "DOM storage", so sites that find themselves unable to use local storage may tell you to check your cookie settings. But Firefox also allows you to disable that independently of cookie settings. Does that sound like something you might have changed, or allowed an add-on to change? You could check here:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste dom.s and pause while the list is filtered

(3) If the dom.storage.enabled preference is bolded and "modified" or "user set" to false, double-click it to restore the default value of true

So the next level would be add-ons that modify how cookies are handled, or anti-tracking features/add-ons.

Can you rule out Firefox's What happened to Tracking Protection? feature?

Could you test in Firefox's Safe Mode? In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Did as you suggested, but the dom.storage.enabled was already on true.

Ruled out the tracking. I tried Firefox in safe mode and still have the same issue:

"Gmail requires cookies to be enabled

Cookies seem to be disabled in your browser. Gmail requires cookies to be enabled in order to operate.

To use Gmail, enable cookies by changing your browser's Preferences or Options. If you have a third-party cookie manager, you will have to configure it to allow cookies from Gmail.

After enabling cookies, try again."

Still unable to access my Gmail account. Also, on Facebook, I can't seem to connect to my "Chat" bar on the bottom right corner after the update. Not sure if it is related. But it's fine on any other browser, including Chrome, and Internet Explorer.

Thank you for all your suggestions! Though it did not work, I appreciate you taking time to comment.

Have you tried restarting your computer?

It could be some other setting that isn't coming to mind, or perhaps corrupted program files. To try to tease that apart, could you test in a fresh Firefox profile.

New Profile Test

This takes about 3 minutes, plus the time to test Google and FB (so probably 10 minutes).

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

Click the Create a New Profile button, then click Next. Assign a name like Nov2017, ignore the option to relocate the profile folder, and click the Finish button.

After creating the profile, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but please ignore them.)

Firefox should exit and then start up using the new profile, which will just look brand new. If Firefox asks about enabling any extensions, just skip over that for now.

Do your sites work any better in the new profile?

When you are done with the experiment, open the about:profiles page again, click the Set as default profile button for your normal profile, then click the Restart normally button to get back to it.

Tried restarting computer, did not help. Though I would have hit myself on the head if it did. Haha.

Tried creating new profile and testing it, did not work as well. I wonder what the issue could be...

I don't have many add-ons either except for the ad blocker plus and ad guard.

dlouie12 said

ad blocker plus and ad guard.

Disable one, then the other.

We're running out of potential explanations for this problem.

To rule out corrupted program files, could you:

Clean Reinstall

We use this name, but it's not about removing your settings, it's about making sure the program files are clean (no inconsistent or alien code files). As described below, this process does not disturb your existing settings. It's not essential to uninstall Firefox, but you can if you like, saying No to any request about removing personal data.

It only takes a few minutes.

(A) Download a fresh installer for Firefox to a convenient location. You can choose between:

Regular version for Windows 7-10 https://www.mozilla.org/firefox/all/

Extended Support Release for Windows XP-10 https://www.mozilla.org/firefox/organizations/all/ Note: Firefox 55-57 profiles are not fully backwards compatible.

(B) Exit out of Firefox (if applicable).

(C) Using Windows Explorer/My Computer, rename the program folder as follows (you might have one or both):

C:\Program Files (x86)\Mozilla Firefox =to= C:\Program Files (x86)\OldFirefox

C:\Program Files\Mozilla Firefox =to= C:\Program Files\OldFirefox

(D) Run the installer you downloaded in step (A). It should automatically connect to your existing settings.

Any improvement?

Have you tried this :

When you're on that site, click on the 'i' in a circle, next to the padlock at the left side of the address bar.

Then click on the little black arrow on the dropdown and then on 'More Information'.

Click on 'Permissions' and scroll down to 'Set Cookies'. Here you unckeck 'Use Default' and check 'Allow'.

The "I" thing didn't work as it was already configured the way you suggested.

Turning off the add-on did nothing.

However, tried a fresh installing through the links you provided for both extended and regular did not work. Uninstalled again twice. Went to the automatic download of Firefox, reinstalled, and it somehow works now. Both the Gmail and Facebook Chat. Not sure what caused it, but thank you for all the suggestions! Greatly appreciated it.

Could be a corrupt file was overwritten. Well done.