4. When You Have Expired Content on Your Site
If you have some expired content, promotion, or events on your blog and you already have related events on your website, you should rather use a 301 redirect instead of a canonical tag.
This is because it would be better for your visitors to visit a page that will be valuable to them and probably give you more customers instead of redirecting them to a page that isn’t valuable.
5. A/B Testing
The A/B strategy is a method used to test which of the elements works best on a webpage. Doing this could make it complicated for Google crawlers to assess your page for the purpose of indexing. A canonical URL is the compass to the original page.
Canonical URL Set up
So far, we have discussed why you should use canonical tags on your website. This article won't be complete without talking about how to add canonical tags to your website. Adding these tags to your website is mostly dependent on your website's plugins.
1. Add Canonical URLs with Yoast
Yoast SEO is known to be one of the most used SEO plugins for WordPress. This tool is used for adding canonical tags.
WordPress site owners can install the free plugin and then add canonical tags to their website through the post section or edit page. This method is ideal for users who do not want to touch the technical elements or code
Where do I find the Canonical Tool you refer to and does it tell you how to add/fix the issues?