Hello! Our help will be more effective, if you copy and send us info about your browser and the Savefrom.Net extension:
http://en.savefrom.net/user.php?info=1
We'd also need some links you can't download (to test them).
For the better understanding it'll be great to see a screenshot with the error.
We are waiting for your reply, and thank you for contacting us Savefrom.net Team!

Hello, for the better understanding it'll be great to see a screenshot with the error. 

Hola y gracias por contactarnos. Por favor, bríndenos algunos detalles adicionales con respecto al problema. ¡Gracias!

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

Hello, this site is not on the list of supported resources. The full list can be found here: http://en.savefrom.net

We apologize for temporary difficulties with. We are working on the fix. 
Meanwhile you can use another browser for now or try televzr app

Hello, please provide us with more detailed information about the problem.

Send screenshots.

Hola y gracias por contactarnos. Por favor, bríndenos algunos detalles adicionales con respecto al problema. ¡Gracias!

https://www.facebook.com/mundopositivoYA/videos/316830628852345/

Try this link on the website.
We checked the links the site downloads them and we have not yet detected any errors.