When I fill in the sign up form twice with the same email address, the contact in Constant Contact is getting updated, instead it should throw an error or do some validation on the form and say the email is already in use.
Is it possible to do any sort of validation on the sign-up form or are there any other ways to do it?
Any help would be appreciated.
Great question! At this time the basic sign up form is designed to update, or over-write information if its identical to other information in the account. This is actually considered an "update" to existing information. If you would like a more custom option it would be worth looking into a custom form. We've got a developer forum where you can do some research or here' s a link to our API page.
I'm happy to pass this feedback along for you. Can you tell me more about why the contacts would be signing up again? Are you asking them to make an update to their preferences?