Hello,
Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.
The canonical is automatically added by Rank math, the URL grayed out. You can just type in a new URL, but please note that modifying the canonical will exclude it from sitemap as Rank math assume that as the reason for modifying canonical URL.
If the canonical URL is not added to your page source, it is likely you have your page set to noindex, in which case even adding the canonical manually will still not appear. You will need to remove the noindex tag for the canonical URL to be shown.
Looking forward to helping you. Thank you.
Great, that cleared things up. Thank you!
Hello,
We are super happy that this resolved your issue. If you have any other questions in the future, know that we are here to help you.
If you don’t mind me asking, could you please leave us a review (if you haven’t already) on https://wordpress.org/support/plugin/seo-by-rank-math/reviews/#new-post about your overall experience with Rank Math? We appreciate your time and patience.
If you do have another question in the future, please feel free to create a new forum topic, and it will be our pleasure to assist you again.
Thank you.