Another option would be to create a sign-up form within your Constant Contact account. We offer a few types of forms:
1.) Lead Generation Landing Pages, which can be linked to a button, image, or text link on your website:
Create a Lead Generation Landing Page
Share the URL for a Lead Generation Landing Page
2.) Inline Sign-up Forms, to be embedded into a webpage:
Create an inline contact sign-up form
Once you have created and published an inline form, there are two pieces of code needed to install the form on your site. The Universal Code connects the form to your Constant Contact account, while the Inline Code identifies which form should be displayed. Both pieces of code should be added to your webpage in the same custom widget, which can be positioned on the page as desired.
Step 2 (Get the code for your sign-up form) in this article explains how to locate both pieces of code within your Constant Contact account:
Activate and install an inline sign-up form on a website
The following Wix Help Center article covers adding a custom widget / HTML iFrame to a page on your site:
Wix Editor: Using iFrames to Display Visible Content on Your Site
3.) We do offer Pop-up Forms, however they unfortunately do not appear to be compatible with Wix websites at this time.
If you have any questions about our Inline Forms or Lead Generation Landing Pages, please contact our Customer Support team at 866-289-2101.