diff --git a/roles/mastodon/templates/mastodon.conf.j2 b/roles/mastodon/templates/mastodon.conf.j2
index 19912c9..234534b 100644
--- a/roles/mastodon/templates/mastodon.conf.j2
+++ b/roles/mastodon/templates/mastodon.conf.j2
@@ -16,7 +16,7 @@ server {
 server {
   listen 443 ssl http2;
   listen [::]:443 ssl http2;
-  server_name {{ mastodon_host }};
+  server_name {{ mastodon_host | default(ansible_fqdn) }};
 
   ssl_protocols TLSv1.2;
   ssl_ciphers HIGH:!MEDIUM:!LOW:!aNULL:!NULL:!SHA;