Hi, next time if there is please do not share info while in Safe Mode. All data that would have helped with your Video Card Drivers are all off. Please uninstall and reinstall your Video Card Drivers for : adapterDescription: NVIDIA GeForce GTX 745 https://www.geforce.com/drivers

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content (Adblock Plus, NoScript, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block (wanted) content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows the shield icon at the left end of the location/address bar in case content is blocked by Tracking Protection.

• click the shield icon for more detail and possibly disable the protection
• You can check the Web Console by Tracking Protection
• "3-bar" menu button or Tools -> Web Developer
• https://support.mozilla.org/en-US/kb/tracking-protection-firefox

cor-el said

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block (wanted) content

The problem exists in safe mode, so it's not a problem with extensions.

Firefox shows the shield icon at the left end of the location/address bar in case content is blocked by Tracking Protection.

• click the shield icon for more detail and possibly disable the protection

There is no shield icon present, either before or after trying to click the video.

Pkshadow said

Please uninstall and reinstall your Video Card Drivers for : adapterDescription: NVIDIA GeForce GTX 745 https://www.geforce.com/drivers

Reinstalled latest GeForce drivers and rebooted. No change.

When I visit the first link and right-click the video, then choose Inspect Element, the Page Inspector highlights this tag in the page:

<video preload="none" playsinline="" style="width: 100%; height: 100%; position: absolute; background-color: black; transform: rotate(0deg) scale(1);" poster="https://pbs.twimg.com/ext_tw_video_thumb/1036403118764777473/pu/img/fnzEHddsQVNJBa8K.jpg" src="blob:https://twitter.com/1957c2d1-2661-4990-9870-2cbd33fe9a47"></video>

Does your Firefox have that tag?

As long as we're in the developer tools panel... you could check for messages in Firefox's Web Console. Click "Console" along the top line next to "Inspector" Or you can open the Web Console using Ctrl+Shift+k).

Then reload the page in the upper part of the tab and watch for error or security messages. (The lines with blue triangles generally are not significant unless you suspect a style rule problem.) Anything that sounds like it could be relevant?

I see that a lot of answers are marked as unhelpful, so there is not much progress so far to troubleshoot this issue.

This is not a normal video as you can see by the code Jscher2000 posted. I had noticed this code as well, but I don't know how blob: data works with videos. I see XHR requests in the Network Monitor to load additional chunks and some requests (application/x-mpegURL) to load stream data.

jscher2000 said

When I visit the first link and right-click the video, then choose Inspect Element, the Page Inspector highlights this tag in the page: <video preload="none" playsinline="" style="width: 100%; height: 100%; position: absolute; background-color: black; transform: rotate(0deg) scale(1);" poster="https://pbs.twimg.com/ext_tw_video_thumb/1036403118764777473/pu/img/fnzEHddsQVNJBa8K.jpg" src="blob:https://twitter.com/1957c2d1-2661-4990-9870-2cbd33fe9a47"></video> Does your Firefox have that tag? As long as we're in the developer tools panel... you could check for messages in Firefox's Web Console. Click "Console" along the top line next to "Inspector" Or you can open the Web Console using Ctrl+Shift+k). Then reload the page in the upper part of the tab and watch for error or security messages. (The lines with blue triangles generally are not significant unless you suspect a style rule problem.) Anything that sounds like it could be relevant?

Interestingly, when I right-click on the the video (on either example page), I get nothing. No pop-up menu, no messages in the developer console. Nothing. It just eats my click. Same for left click.

Well over a minute after clicking the video, the video still-frame changes to "This media could not be played" and these messages finally appear in the developer console:

Unhandled promise rejection undefined init.en.099263799c98fd59dd4a.js:2:99500 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:99500 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:98900 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:99377 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:14:20833 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160163 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160021 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160041 Source map error: request failed with status 404 Resource URL: https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js Source Map URL: init.en.099263799c98fd59dd4a.js.map[Learn More] Unhandled promise rejection undefined init.en.099263799c98fd59dd4a.js:2:99500 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:99500 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:98900 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:99377 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:14:20833 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160163 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160021 https://abs.twimg.com/k/en/init.en.099263799c98fd59dd4a.js:2:160041

Hi, please try a Refresh but Note that this does more than uninstalling and re-installing does. Normal uninstalling does not remove some preferences which may have become corrupt. Please Refresh but do this 1st:

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

then

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

haydentech said

Interestingly, when I right-click on the the video (on either example page), I get nothing. No pop-up menu, no messages in the developer console. Nothing. It just eats my click. Same for left click.

Hmm, maybe that's related to the delay in loading? Another way to inspect an element is to open the Inspector using Ctrl+Shift+c, which makes "click to select" active.

The Web Console messages suggest that some content is blocked from loading. Is Firefox's Tracking Protection feature kicking in? You would see a "shield" icon next to the padlock at the left end of the address bar in that case. (What happened to Tracking Protection?)