There's a configuration issue that can confuse Google about which version of a page to rank. This can split your SEO value across duplicate pages, making all versions rank lower.
On WordPress
Yoast SEO and Rank Math automatically add correct canonical tags. If you've manually overridden a canonical in the SEO plugin settings, verify it's pointing to the right URL.
On Shopify
Shopify adds canonical tags automatically. Issues usually appear when collections have pagination or when product URLs appear in multiple collections. Check Online Store → Themes → edit theme code for custom canonical logic.
SiteSprout scans your site, tells you which issues you actually have in plain English, and keeps watch so nothing breaks silently.
Scan your site free