Update URLs is not working!

Hello!

I tried Velvet Blues plugin for updating my website links from non www version to www version of the website and without success. After updating the plugin says success, but there are still a lot of links weren’t updated.

Also, I tried to put my URL like
Old – http://mydomain.com/
New – http://www.mydomain.com/

But the pluging didn’t get it, so I ended entering:

Old – mydomain.com
New – http://www.mydomain.com

Is that OK?

Thanks.

https://wordpress.org/plugins/velvet-blues-update-urls/