When I try to create a new page in wordpress, then go to viewing mode, the following text appears in a red bar: “Updaten mislukt. De reactie is geen geldige JSON-reactie.” Dutch for: “update crashed, respons is no valid JSON-respons.”. Also, all pages show homepage when stepping out of editor mode into viewing mode. All pages show the homepage, not the edited page. When returning to the edited page the same red bar with same notification is shown. Also some content (a block) cannot be loaded. Page shows the following notification: Fout bij laden blok, de reactie is geen geldige ISON-reactie. Translated: Cannot load block because of invalid JSON response.
To resolve the issue, please follow the steps below:
1οΈβ£ Update Permalink
Go to Settings > Permalinks in your WordPress dashboard.
Click Save Changes without changing anything. This refreshes the permalink structure and can resolve some issues.
2οΈβ£ Disable Plugins
Deactivate all plugins to see if one of them is causing the issue.
If the problem goes away, reactivate the plugins one by one to identify the culprit.
3οΈβ£ Switch to a Default Theme Temporarily switch to a default WordPress theme (like Twenty Twenty-Four) to check if your current theme is causing the issue.
4οΈβ£ Check Site Health Navigate to Tools > Site Health and check for any critical issues that might need addressing.
Resetting permalinks don’t work, neither does deactivating extra-installed plugins. I am not sure how to change the theme back into the original and Site Health shows two issues, its not clear what they mean.
However before trying any of these: Could the problem be caused by setting “Site adres URL” under “settings>general>Site adres URL” to one of the pages URL. This page shows up if viewing any page in viewing mode.