Could you confirm that Flash is permitted on Facebook (specifically on apps.facebook.com)? When a game that requires the Flash plugin is loading, a notification icon should appear toward the left end of the address bar. It looks like a small, dark gray Lego block. If you click that, does it show that Flash is allowed or that Facebook needs permission to use Flash? You can update the permission using the buttons there if needed.

Thanks, that's not it. The little lego in the upper left says Flash is allowed, not blocked on Facebook. And Firefox says it has insecure content, but not blocked by Firefox. Pop ups allowed.

I don't know whether it's relevant to a brand new Firefox installation -- it may vary based on whether Firefox imported data from another browser or through Sync -- but you could try "the usual":

If a site is generally known to work in Firefox, these are general suggestions to try when it stops working:

Cache and Cookies: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache

If you have a large hard drive, this might take a few minutes. If you do not see the number going down on the page, you can reload it using Ctrl+r to check progress.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click (on Mac Ctrl+click) a blank area of the page and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"
• click the padlock or "i" icon in the address bar, then the ">" button, then More Information, and finally the "View Cookies" button

In the dialog that opens, the current site should be pre-filled in the search box at the top of the dialog so you can remove that site's cookies individually.

Then try reloading the page. Does that help?

Check Cookie Settings: This article identifies the key issues that affect site operations: Websites say cookies are blocked - Unblock them.

Testing in Firefox's Safe Mode: In 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? (More info: Diagnose Firefox issues using Troubleshoot Mode)

Ok, that was helpful. Thank you. I opened in Safe Mode, with add ons disabled. And it worked. So, How do I identify what add on is causing the problem, so I don't have to play in Safe Mode?

If you pretend you know nothing about the extensions, you can disable half, restart to test, then if that doesn't work, it must be in the other half, etc., process of elimination. But if you look at extensions that block some content, whether ad blockers, script blockers, or tracking blockers, you can experiment with making exceptions to see whether that resolves it.

Either way, you can view, disable, and often configure or remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions that Firefox installs on its own are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything that looks like it might block content? Try its Options button. Anything you don't really need? If in doubt, disable.

Often a link will appear above at least one disabled extension to restart Firefox before the change takes effect. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

So, Thanks again. Nothing new, however. Under Extensions, I have NO extensions. "You don't have any add-ons of this type installed." No Services either Under Plugins, I have 3: OpenH264 Video Codec Provided by Cisco Systems. Always Activate Shockwave Flash 26.0 r0 Always Activate Widevine Content Decryption Module provided by Google Always Activate

Could those be any problem? If not, what else is Safe Mode turning off? Scott

Safe Mode also disables hardware acceleration, meaning that it will not try to use your graphics card/chipset for computing fonts and graphics. You can test that manually:

Windows: "3-bar" menu button (or Tools menu) > Options Mac: "3-bar" menu button (or Firefox menu) > Preferences

In the left column, click Advanced. On the right side, with the "General" mini-tab active, uncheck the box for "Use hardware acceleration when available".

This takes effect the next time you exit Firefox and start it up again. Any difference?

Since hardware acceleration improves the appearance of fonts and animations, you may want to check whether graphics card/chipset driver updates are available for your system. This article suggests safe ways to do that: Upgrade your graphics drivers to use hardware acceleration and WebGL.

Safe Mode also disables the JavaScript compilers, but it's hard to see how those are relevant.

Under Debugging Extensions, I found these:

Application Update Service Helper

Click to Play staged rollout

Firefox Screenshots

Follow-on Search Telemetry

Multi-process staged rollout

Pocket

Shield Recipe Client

Web Compat

Could any of those be a problem, and how would I disable them? I just see Debug as an option.

I think those are Mozilla extensions installed by Firefox itself. Since you already verified Allow permission for FB earlier in this thread, "Click to Play" shouldn't be a problem. None of the others appear to be related to Flash.

Also, the game INSISTED I load Flash, or it would not work. So when I go into safemode, and turn OFF the shockwave, why would it THEN work? Confusing. Should I uninstall the Shockwave?

The label "Restart with add-ons disabled" is not strict correct. Firefox's Safe Mode does not disable the Shockwave Flash plugin, it only disables extensions, hardware acceleration, custom style rules, JavaScript compilers... probably some other things I can't remember any more.

When you are not using Firefox's Safe Mode, do you visit FB in a normal window or a private window? If it's a private window, do you see the "shield" icon on the left end of the address bar? More info on Tracking Protection in this article: What happened to Tracking Protection?.

Always a regular window. I was not aware of the private window until I read your post.

I guess I need to identify all the things Safe Mode actually turns off, and turn them off one at a time. I've googled it, and can't seem to find a list.

Scottpi said

I guess I need to identify all the things Safe Mode actually turns off, and turn them off one at a time. I've googled it, and can't seem to find a list.

This is the best list I'm aware of: http://kb.mozillazine.org/Safe_Mode

The JavaScript compilers have a lot of associated preferences so unfortunately I can't give you a pinpoint intervention for those.

So, out of my depth here. I read that helpful page, thank you.

 Of all the things turned off by Safe Mode, what is most likely to generate that initial error message, and also would NOT bother IE, which plays the game fine?

"To display this page, Firefox must send information which will repeat any action (such as a search or order confirmation) that was performed earlier."

I believe that message indicates that a POST request is being resent. You get the warning because if Firefox were, say, submitting your payment for some product, Firefox would potentially be doubling your payment. In that case, you might want to cancel the second send.

I don't know why that would come up in the context of the game. ??

Neither do I . . . So weird that it's only Firefox, and only in regular mode. It's not a huge sacrifice to switch to Safe to play it . . . it's just weird that no one else seems to have this problem, or Cookie Jam would be all over it!