Hello. Thank you for contacting the Toolset support.
Based on the screenshot you shared I see the error that site key is not matching. Can you please share what site key you generated as well as admin access details?
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.
Can you please try to create a new site key and remove existing site key and try to register the site using the newly created site key and let me if if that works now.