The site was already added earlier”. Why I get this in my Live Chat?

I tried to add the website in my admin area but I cant add it. I get the notification “The site was already added earlier”. How to fix this issue? 

This error may occur in several cases: 

1) your website has been already added to another account of yours;

2) you deleted and added one and the same website for several times. 

In the first case, we would recommend to delete your website from the admin area where you do not need it and add it again to the admin area from which you want to use your chat.