When viewing SSL certificates, what does "Not applicable for SNI" mean?

Issue

When inspecting the SSL certificates uploaded for your application, SNI certificates have "(Not applicable for SNI)" in the "Endpoint" column

Resolution

This only occurs if you have provisioned the SSL Endpoint addon in addition to having SNI setup. SNI certificates use the Heroku Router to terminate the secure connection, and do not require their own SSL Endpoint. Once the SSL Endpoint has been deprovisioned, this warning will also be removed.