Nick here from Shopify.
This normally happens if you had a store, then closed that store and opened a new one without disconnecting your domain from the first store.
There is a topic in the community going through all the steps you need to take to get this fixed. It will require you to reach out to the support team directly to verify the stores so the support advisor can make the changes. You can see the topic here. Let me know if you have any questions about this.
All the best, Nick