Hello. Thank you for contacting the Toolset support.
Can you please send me wp-admin access details so I can check further what is the thing causing the issue.
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin and FTP) 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.
I tried to register the plugins and I am able to successfully register the Toolset plugins.
I suggest you delete the existing site key you created and try to create a new site key by clicking on the "my account" link as shown in the following screenshot, that will create a new site key automatically for your domain and you should copy that site key and try to register it.
=> hidden link