diff --git a/src/ddns_service/models.py b/src/ddns_service/models.py
index fa6ac8c..5d27e57 100644
--- a/src/ddns_service/models.py
+++ b/src/ddns_service/models.py
@@ -9,6 +9,7 @@ from peewee import (
     CharField,
     DateTimeField,
     DoesNotExist,
+    fn,
     ForeignKeyField,
     IntegerField,
     Model,
@@ -297,7 +298,7 @@ def get_hostname_for_user(hostname: str, user: User):
     Raises:
         DoesNotExist: If hostname not found or not owned by user.
     """
-    fqdn = Hostname.hostname + '.' + Hostname.zone
+    fqdn = fn.Concat(Hostname.hostname, '.', Hostname.zone)
     return Hostname.get((fqdn == hostname) & (Hostname.user == user))