I have the same problem. It reloads the entire page instead of showing the errors or the thank you message in the same lightbox.
I had the same problem. You need to keep (Submit via AJAX (without page reload)?) On from the form setting. It is working for me.
Md. Jahidul Islam you rock dude! Thanks heaps.
For anyone hwo didn’t understand this advice, you have to tick the box ‘Submit via AJAX(without page reload)?’ in the ‘Settings’ tab (then click open the ‘Display’ tab) of each form where you want this functionality.
Don’t look in the ‘Ninja Settings’ cos this option ain’t there!
Too bad we don’t actually get ‘support’ from Ninja personnel. But hey, ‘free’ is a pretty good price for this plug-in.