Hello, we've found the solution how to make Savefrom work in Safari.
Install the Tampermonkey extension: https://safari-extensions.apple.com/?q=tampermonkey
Install the Savefrom script: https://download.sf-helper.com/chrome/helper.user.js?ts=1537523278787

Hello, Could you please send a few links you can't download. We will check it out.

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

We checked the video is downloading.

Do you use any proxy? What’s your country?

Thank you for using our extension SaveFrom.net Helper

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

Ok, we'll try.

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, please, send us more details regarding the problem.