hello, could you go to the firefox menu ≡ > help ? > troubleshooting information, copy the contents of that page and paste them here into a reply on the forum? this might give us a clue what is going on...

Give Firefox a tune up Try Safe Mode Troubleshooting Information This page contains technical information that might be useful when you’re trying to solve a problem. If you are looking for answers to common questions about Firefox, check out our support website. Application Basics Name Firefox Version 49.0.2 Build ID 20161019084923 Update History Update Channel release User Agent Mozilla/5.0 (Windows NT 6.2; rv:49.0) Gecko/20100101 Firefox/49.0 OS Windows_NT 6.2 Profile Folder Enabled Plugins about:plugins Build Configuration about:buildconfig Memory Use about:memory Performance about:performance Registered Service Workers about:serviceworkers Multiprocess Windows 1/1 (Enabled by default) Safe Mode false Profiles about:profiles Crash Reports for the Last 3 Days Report ID Submitted

All Crash Reports (including 6 pending crashes in the given time range) Extensions Name Version Enabled ID Awesome Screenshot - Capture, Annotate & More 3.0.14 true jid0-GXjLLfbCoAx0LcltEdFrEkQdQPI@jetpack Emoji Cheatsheet for GitHub, Basecamp etc. 1.2.0 true jid1-Xo5SuA6qc1DFpw@jetpack Multi-process staged rollout 1.3 true e10srollout@mozilla.org Pocket 1.0.4 true firefox@getpocket.com Video DownloadHelper 6.1.1 true {b9db16a4-6edc-47ec-a1f4-b86292ed211d} Web Compat 1.0 true webcompat@mozilla.org Graphics Features Compositing Direct3D 11 Asynchronous Pan/Zoom wheel input enabled WebGL Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics 3000 Direct3D11 vs_4_1 ps_4_1) Hardware H264 Decoding Yes; D3D11 blacklisted with DLL igd10umd32.dll (9.17.10.4229); Using D3D9 API Direct2D true DirectWrite true (6.2.9200.17568) GPU #1 Active Yes Description Intel(R) HD Graphics 3000 Vendor ID 0x8086 Device ID 0x0116 Driver Version 9.17.10.4229 Driver Date 5-26-2015 Drivers igdumd32 igd10umd32 igd10umd32 Subsys ID 13c71043 RAM Unknown Diagnostics AzureCanvasAccelerated 0 AzureCanvasBackend direct2d 1.1 AzureContentBackend direct2d 1.1 AzureFallbackCanvasBackend cairo failures CP+[GFX1-]: [D2D1.1] 4CreateBitmap failure Size(28,30647) Code: 0x80070057 format 0 Decision Log D3D9_COMPOSITING disabled by default: Disabled by default Failure Log (#0) CP+[GFX1-]: [D2D1.1] 4CreateBitmap failure Size(28,30647) Code: 0x80070057 format 0 (#1) CP+[GFX1-]: [D2D1.1] 4CreateBitmap failure Size(11,12871) Code: 0x80070057 format 0 Important Modified Preferences Name Value browser.cache.disk.capacity 358400 browser.cache.disk.filesystem_reported 1 browser.cache.disk.smart_size.first_run false browser.cache.disk.smart_size.use_old_max false browser.cache.frecency_experiment 4 browser.download.importedFromSqlite true browser.places.smartBookmarksVersion 8 browser.sessionstore.upgradeBackup.latestBuildID 20161019084923 browser.startup.homepage_override.buildID 20161019084923 browser.startup.homepage_override.mstone 49.0.2 browser.tabs.remote.autostart.2 true browser.tabs.warnOnClose false browser.urlbar.daysBeforeHidingSuggestionsPrompt 2 browser.urlbar.lastSuggestionsPromptDate 20161111 dom.apps.lastUpdate.buildID 20161019084923 dom.apps.lastUpdate.mstone 49.0.2 dom.apps.reset-permissions true extensions.lastAppVersion 49.0.2 gfx.crash-guard.d3d11layers.appVersion 49.0.2 gfx.crash-guard.d3d11layers.deviceID 0x0116 gfx.crash-guard.d3d11layers.driverVersion 9.17.10.4229 gfx.crash-guard.d3d11layers.feature-d2d true gfx.crash-guard.d3d11layers.feature-d3d11 true gfx.crash-guard.status.d3d11layers 2 gfx.crash-guard.status.d3d9video 2 media.benchmark.vp9.fps 95 media.benchmark.vp9.versioncheck 1 media.gmp-manager.buildID 20161019084923 media.gmp.storage.version.observed 1 media.hardware-video-decoding.failed false network.cookie.prefsMigrated true network.predictor.cleaned-up true places.database.lastMaintenance 1478806382 places.history.expiration.transient_current_max_pages 51174 plugin.disable_full_page_plugin_for_types application/pdf plugin.importedState true plugin.state.npgoogletalk 2 plugin.state.npgoogleupdate 2 plugin.state.npo1d 2 security.disable_button.openDeviceManager false services.sync.declinedEngines storage.vacuum.last.index 0 storage.vacuum.last.places.sqlite 1478806382 ui.osk.debug.keyboardDisplayReason IKPOS: Touch screen not found. user.js Preferences

Your profile folder contains a user.js file, which includes preferences that were not created by Firefox. Important Locked Preferences Name Value Places Database Integrity JavaScript Incremental GC true Accessibility Activated false Prevent Accessibility 0 Library Versions Expected minimum version Version in use NSPR 4.12 4.12 NSS 3.25 3.25 NSSSMIME 3.25 3.25 NSSSSL 3.25 3.25 NSSUTIL 3.25 3.25 Experimental Features Name ID Description Active End Date Homepage Branch

thanks, which security software are you using? and does it make a difference when you refresh firefox?

no,refreshing firefox isn't helping

In order to better assist you with your issue please provide us with a screenshot. If you need help to create a screenshot, please see How do I create a screenshot of my problem?

Once you've done this, attach the saved screenshot file to your forum post by clicking the Browse... button below the Post your reply box. This will help us to visualize the problem.

Thank you!

codes like these.

Do you have any software that filters your connections to websites? A while ago there was a problem with Kaspersky software -- since fixed -- that caused Firefox users to receive gibberish from Facebook.

I'll give you the temporary workaround for that problem to see whether it makes any difference for you:

(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.

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

(3) Double-click the network.http.accept-encoding.secure preference and edit as follows: delete the , br from the end so it just reads gzip, deflate like the preference above it in the list, and then click OK

What that does is stop Firefox from telling Facebook it can use "Brotli" compression. Facebook will use the older gzip form of compression instead.

Any difference? If so, we should try to figure out what is wrong with your web filtering software (or whether you have malware intercepting your connection).

ok, so i'm gonna guess that you're a user of kaspersky software. unfortunately that garbled text on faceboopk will be caused by a fault in kaspersky on your device which meddles with your connections. the issue should be fixed by kaspersky already when you update its software to the latest version/signature.

in case this didn't work, please proceed like this:

• go to kaspersky Settings > Additional > Network > Traffic Processing and uncheck the "Inject script" setting.
• in addition, disable the scanning of secure connections like it's described at https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER#w_kaspersky and reboot your system afterwards.

https://forum.kaspersky.com/index.php?showtopic=351027

Sorry but i at the moment don't know if there's any kaspersky software or any other software installed,but facebook is now working after editing that ,br thing.Is it not a permanent solution?

abhi.n said

facebook is now working after editing that ,br thing. Is it not a permanent solution?

Here's the thing: it absolutely should not be necessary to change that. It almost certainly means there is a "man in the middle" between your Firefox and Facebook.

To get a better idea of what is going on, could you take a look at the certificate? While viewing a page on Facebook, try either:

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

When there is a "man in the middle" the certificate issuer usually does not match the true issuer. Please compare the information you see with the attached screenshot. Any differences?