Why do I receive the Apache error "Hostname * provided via SNI and hostname example.com provided via HTTP have no compatible SSL setup"?

Question

Why do I receive the Apache error "Hostname * provided via SNI and hostname example.com provided via HTTP have no compatible SSL setup"?

Answer

This error is the result of a possible attack called "virtual host confusion". The idea is that a mismatch between the target name in the TLS handshake ("provided via SNI") and the target name in the HTTP protocol ("provided via HTTP") can be exploited.

The error message received shows that the behavior was correctly blocked.