Cookie is a small file on your computer to store information when you visit a website. Your browser may block a third-party cookie to protect your privacy. Most Shopify apps are using cookies to optimize your usage experience and so does SPO. If you see this message, there are 2 possibilities:
- Your current browser (say Chrome) blocks 3rd party cookie
- You are using Safari or other browsers that block cookie
For 1, you'll see an icon on the url field (screenshot attached). You need to allow the cookie on for SPO site. Click "Show cookies and other site data"
Allow the cookie for app.seo-product-optimizer.com. Reload the tab and it'll be done.
For 2, please follow the instructions to activate cookies.