Your video URL is incorrect.
==> Make sure to visit that URL first to ensure there is a video appearing there before you try it on TubeOffline.
This is what you entered:
Your video URL has a PRIVATE video.
==> Only VK private videos are downloadable at the moment.
If you have a link to private video on another site, try this method it may work for your site.
Your video URL is correct but you are using WRONG downloader.
==> If you have a PUTLOCKER video link, then use PUTLOCKER downloader.
Facebook video link? Use Facebook downloader. OK? :)
The downloader is down and needs to be updated.
==> If you are 100% sure your link is correct and still won't download, then that downloader is down.
LET US KNOW so we fix it.
We usually respond within 24-48hrs.
Use the HELP button on the topbar.