"The distribution you are trying to delete has not been disabled."


<img width="889" alt="Screenshot 2020-05-13 16 27 58" src="https://user-images.githubusercontent.com/5825789/81818468-be32e300-9536-11ea-9754-8d0b208e9818.png">
I am trying to unbind the subdomain. And receive an error that distribution is not disabled. 
Please clarify, what does it means and why I should disable it?