"Alternate page with proper canonical tag" in Google Search Console - 18 Page Errors

[LeithW6]

Hey Community,

I've having issues with duplicate pages and "Alternate page with proper canonical tag" in Google Search Console. I've got 18 page errors, watched numerous YouTube videos on how to fix and I still can't solve the issues. Please Help!

Google is also recognising product pages that don't exist any longer on my Shopify store

www.henleybeachproteinco.com.au