If you are hosted on GoDaddy and using their Firewall via Sucuri, and get the error below when trying to update a Post using the WordPress block editor:
Updating failed. The response is not a valid JSON response.
… this may be due to the firewall settings at GoDaddy.
To see if this problem may be affecting your site, you can verify this by doing the following.
Check for REST API Errors
You can see details of any possible REST API error in the WordPress Site Health tool. Visit the Tools » Site Health page in your backend.
If you see something like the below, this is indicating that there is an error with the firewall at GoDaddy.
Add Your IP Address to GoDaddy
While there are other options and settings you could try with the firewall (including turning it off), the solution below will allow you working from your computer to stop receiving this error and continue with saving your posts in the WordPress Block Editor.
- – Get your computer’s IP address at https://whatismyipaddress.com/
- – Login to your GoDaddy.com account
- – Go to Manage My Products -> Security -> Firewall -> Settings -> Access control -> Allow IP Addresses
- – Add your IP address in the field below
You should be able to save your post without errors!