This worked for 2 years. Today I received a crawl error from google search console:
Coverage issues detected on XXX
Search Console has identified that your site is affected by 1 Coverage issues:
…
The following errors were found on your site:
Duplicate without user-selected canonical
I have no idea what is the exact reason for the error or how to fix it.
Thank you for any help
Duplicate without user-selected canonical: This page has duplicates, none of which is marked canonical. We think this page is not the canonical one. You should explicitly mark the canonical for this page. Inspecting this URL should show the Google-selected canonical URL.
Here is a tool to check the link/page, its linked above too