Sometimes strange behavior may be caused by a plugin or theme conflict. The fastest way to rule out conflicts is to deactivate all non-Yoast plugins and switch to a standard theme like Twenty Seventeen. If this resolves the issue, you have a conflict and should activate one plugin at a time until you locate the conflict. Finally, after all plugins are active, switch to your theme. This will narrow down the conflict to a specific plugin or theme.
If you are unfamiliar with checking for conflicts, we wrote a small guide that will walk you through the steps. You can find it here: How To Check For Plugin Conflicts
Hi Amboutwe,
Thank you for your reply.
I followed your steps already and narrowed down the problem lies with the Anspress plugin. I figured out it overwrites the WordPress canonical hook and stripped it from all the pages except for their own.
Fixed it myself in the plugin code and noticed the developer.
Thank you for the support.
Case closed.