Hello, from which site and where exactly do you install the extension? Send link.

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

Hello, we’d like to help you, but we will need some info about your browser and the installed extension first.
Please, go here http://en.savefrom.net/user.php?info=1
Copy the details that you see and send them back to us.
Please also send us some video links that you can’t download.
Thank you for contacting Savefrom.Net support !

Здравствуйте, мы знаем об этом и делаем всё возможное что бы это исправить.

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

Send a link to the playlist and links to videos that you do not download in the playlist.

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

Hello, Yes, we are aware of this issue. And doing our best to fix it ASAP.
Thanks for using our resources.
Best, SaveFrom.net Team

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.

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

Hello, Please, use our extension Video Downloader Pro: http://videodownloaderpro.net
Possibly, it will download from the website you want.