The issue is not from Gutentor but sometimes while using Gutenberg the following issues may come.
Updating failed. Error message: The response is not a valid JSON response.
Publishing failed. Error message: The response is not a valid JSON response.
Quick Solutions:
- Go to Settings => Permalinks. Select Post name and save.
- If it is already selected, you can just click Save Changes again.
- Make sure Rest API is working fine on your website.
- After that try to save your post/page again
Most of the time the Quick Solutions fix the issue.
Next Solutions:
- Make sure your installation meets the server requirement.
- Deactivate plugin one by one and try to save the post, if the plugin is causing this, you will find it.
- Delete revision post using any of the delete revision plugins.
Check if the issues are fixed.
Final Solutions:
- From your Cpanel file manager or FTP, go to WordPress installation and write the following code on wp-config.php, see WP DEBUG
define( 'WP_DEBUG', true ); define( 'WP_DEBUG_LOG', true );after that try to save the post and view the debug.log log file inside the /wp-content/ folder. There should be an error. Try to solve that.
- From your Cpanel file manager or FTP, go to WordPress installation and delete the .htaccess file. After that from WordPress Dahbboard to Settings => Permalinks. Select Post name and save.
If you are not able to solve the issue, you can contact us with the debug.log files and browser console issue (if any) on Gutentor Support.