Invalid JSON response

Hi @andreas-peters and thanks for opening a support topic and sharing the information you have so far. We’ll need to perform some checks to determine why you’re unable to set up the plugin. In order to do so, please share the following:

1. Your full  Site Health information. You can use this form to share privately if preferred.  
2. Do you see any warnings or errors when checking your Site Health status  (Tools > Site Health > Status), which differs from your Site Health information shared previously? Such errors may include REST endpoint references.
3. What is your current location? I ask as Google services are blocked in some regions, and this can be one such reason for the final error you reported.
4. Have you been able to set up Site Kit on this site previously, or on any other site on the same hosting platform?

Let me know if you have any questions with the above.

@andreas-peters Thanks for sharing the information that’s very helpful. With regards to point number 2, I was asking for your Site Health status  (Tools > Site Health > Status), which differs from your Site Health information which you shared in the screenshot.

Could you first please try following the troubleshooting steps here to see if you are still seeing the error while in troubleshooting mode with just Site Kit active on your site.

@andreas-peters Thanks for your continued efforts in troubleshooting this. You can also try performing a Site Kit reset. Please note that resetting Site Kit disconnects all users and removes all Site Kit settings, Dashboard Sharing settings and data within WordPress. After resetting, other administrators will need to go through the setup process again. Any users that have access to a view only dashboard will lose access to them.

You may also want to check in with your hosting provider to ensure that there are no firewall or other security settings that may be blocking any Google services.

Let me know how you get on with the above.