Stop form submission and return error message

[chrishajer (Chris (Gravity Forms))]

It sounds similar to the discussion here:

Stop form submission and make user enter a field if response is zero [RESOLVED]

Hi Team, I am sending the form data to external url. I am trying to do something like this : If Reponse == 0 don’t submit form Make user renter the value of a form field saying something like “Please enter a valid address” else Submit form I am not sure what filters and functions to use to make it work. Regards, Pallavi