I am seeing this message in the backend. In installer support all messages are ticked green. The message at the top is from before I registered Toolset. It has now been registered but I am still seeing the message "Toolset plugin cannot connect to toolset.com".
Hello. Thank you for contacting the Toolset support.
I can see with the screenshot that is shows the message that site key is not matching. What if you try to register a new site key and delete the existing one - does that helps?
If your site key is already registered, what if you navigate to:
=> Dashboard => Updates => and click on " Check again." link.
*** 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.