If you want that some IPv6 users can access your store, then you have to select this feature and follow the below steps.

Firstly, click on the Whitelist IPs from the side menu in the app,

Start From Here:-

A. Click on the IPv6 IPs button from the menu

B. Now click on the ADD NEW IP button

After that, a page will be opened, Then do the following steps:-

1) Enter IPv6 IP ⇒ Add the IPv6 IP 

2) Now click on the SAVE TO WHITE LIST button to add the IP to the White List IPv6 IPs.

If you want to delete/edit The IPv6 IP:-

1) Click on the Trash/Edit icon to delete/edit the IP from the Whitelist list.