Mailchimp is not linking with my Mailchimp Email SignUp app - Shopify

The Mailchimp Email SignUp app is no longer supported which is causing the issue.

Please try to create a Popup app instead using one of the links below and see if that makes any difference on your end.

https://www.powr.io/plugins/popup / https://apps.shopify.com/powr-popup

And connect to Mailchimp: Connect Popup to any app using Zapier