Questions using Rainmaker with Icegram campaign

Hello, using the latest versions of wordpress and plugins icegram, rainmaker, and Email subscribers.

The campaign looks great on the website and I love how the name field is mandatory as well.

However, after clicking submit, I get taken to a new white page with only “0” displayed on the top left corner without the quotation marks, and nothing else. I don’t receive a confirmation email, and I don’t see the new subscriber.

What could be causing this?

Please note: I do not wish to disclose the website name here at this time if ok with you. I’m only looking for possible causes. Thank you.