Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Could you please send a few links you can't download. We will check it out.
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Could you please send a few links you can't download. We will check it out.
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Hello, in order to help you better I need the following information.
Please, send me the information listed here: http://en.savefrom.net/user.php?info=1
Could you please send a few links you can't download. We will check it out.
Do you download via the extension SaveFrom.net Helper or the website SaveFrom.net?
For the better understanding it'll be great to see a screenshot with the error.

Clear your browser:

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

Hello, Unfortunately, we don't fully understand you... please. provide us with more details regarding the issue.

For the better understanding it'll be great to see a screenshot with the error.

Hello, please, send us more details regarding the problem.

Ummy Video Downloader cannot download this video in high quality, even if on Youtube 1080p.

Youtube does not give it to download in high quality.

Hello, unfortunately Youtube itself does not give download this video in higher quality.