SSH can use a domain name but can not use a server name!

Something very strange happened to my server.

From home (where is also my server), I used ssh with my server name. From the outside, I ssh uses my domain name, which obviously points to my home server. However, since today, I can not use ssh on my server using the name of my server from my home.

I can not understand why, I did not make any changes. Does any body know what could be causing this problem?

I'm using mobaxterm to ssh if that helps. I also use pub / priv ssh key.

Update:

I'm trying to SSH using the name of my server, very rarely, it works, but most of the time, it is written "the host does not exist"

Thank you