Make sure you are not blocking content.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

FredMcD said

Make sure you are not blocking content. Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Did what you asked. But the problem is still there. Hmm. You said blocking content, I don’t understand that. How can one block a content using a browser? I’m confused.

adblocker, cookie blocking or noscript will block things that are needed for video viewing from a site.

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

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Note: Any customization will revert back to default, you will also need to reinstall Extensions.

Please let us know if this solved your issue or if need further assistance.

Twitter videos hosted on other websites may not work due to CSP violation errors. The Web Console will show a security error message in such a case. You check if there is a link to open the video on the Twitter website.

• https://developer.mozilla.org/Security/CSP

You can right-click the media player area with the error message and use "This Frame -> View Page Info" to see if this is about content hosted on Twitter.

This is a problem with Twitter that uses CSP policy rules that prohibit a browser that supports this security feature from playing this content embedded on another website. You can look for a link to open the video on the Twitter website. A possible workaround is to disable CSP temporarily in Firefox to be able to see the video.

• /questions/1196774 What is Mozilla doing about Twitter embedded videos violating CSP?

You can disable CSP by toggling this pref to false on the about:config page.

• security.csp.enable = false

Since this is a security feature you shouldn't leave it disabled.

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• http://kb.mozillazine.org/about:config

Pkshadow said

adblocker, cookie blocking or noscript will block things that are needed for video viewing from a site. 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

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Note: Any customization will revert back to default, you will also need to reinstall Extensions. Please let us know if this solved your issue or if need further assistance.

This helped me a little bit. Right now I can view SOME of the videos hosted on Openload. But it's not now one-time thing. I can view them at any time. But on some wesites I can't. I'm guessing this problem is about those websites?

Yes! It was about those websites embedding the videos. I opened them on their original host pages on Openload, and it's working now. Thank you!