How to Change Form Warning Messages

How can I change the text, when someone forgets to fill a required box. It says Whoops! looks like you missed something!

Hello skocznia,

I think the one you're referring is the "Form Warning" message. Please follow the Steps below for your info.

1. Click “Preferences”.

2. Click “Advance Settings”.

3. Click “Edit Form Warning”.

4. Click  and change “This field is required.” to “Whoops! looks like you missed something!”

5. Example: http://form.jotform.me/form/50443315634449 

Cheers!