I've upgraded from Magento 1 to Magento 2. Everything is working fine otherwise, but the product links found in Google for the site result in a 404 page due to the URL structure having changed. I sent a new sitemap to Google about a week or two ago but it has not helped the situation. Google Search Console reports nearly 15,000 unfound pages.
For example, searching Google with product number "9480662" results in this link:
Whereas the correct URL for the product is this:
This may be due to the M1 installation having an SEO extension that changed how URLs were set up in the store, which is not present in the new installation.
How can I correct this?