Multiple SSL certificates

[Thomas]

So I tried with my real IP server, and it works. But when I add my IP
failover, it doesn't.

How do I configure the IP on the host? Why would the host need to be
aware of its IP? Moreover, Nginx is running in a virtual machine, the
only IPs it is aware of are 127.0.0.1 and 10.0.0.1

And why do I need to configure any IP, as Nginx works with the real IP
of my server, why is it not working with the IP failover? By the way
the IP failover is correctly pointing to my server.