>>> [!note] Migrated issue <!-- Drupal.org comment --> <!-- Migrated from issue #3547294. --> Reported by: [hooroomoo](https://www.drupal.org/user/3688872) Related to !139 >>> <h3 id="overview">Overview</h3> <p>1. If a piece of content that is set to be used in the content template preview has been deleted, then clicking that template in the menu results in a 404 since the content no longer exists. The only way out of that is to remove the node from the URL, otherwise the page is stuck with a 404. </p> <p>Aka <code>/canvas/template/node/article/full/1</code> if I delete node 1 then clicking the template item again will result in a 404. </p> <p>So add an error boundary to handle 404 and have a button in the error boundary to redirect to <code>/canvas/template/node/{bundle}/{viewMode} </code> which will either re-route itself to the next existing <code>suggestedEntityId</code> or to the state where a user is shown the "No content available" screen with the button to create a new piece of content.</p> <p>2. If a user has a template open then deletes the template, we can just show an error message the same like we do when a user doesn't have any existing content yet.</p> > Related issue: [Issue #3541000](https://www.drupal.org/node/3541000)