This is a very common error which we get while working on wordpress new block editor.
” Updating failed. Error message: The response is not a valid JSON response. “
The easiest way to resolve this error is listed below.
From your wordpress dashboard from left hand side options
- click on settings at the bottom.
- select permalinks
- Select the option plain
- click on save button
- now check your website pages in other tab. hopefully they are now opening.
- now change the permalink back to your Post name
- Now you can open the pages and your website is working fine.