diff --git a/app/models/activity_pub/instance.rb b/app/models/activity_pub/instance.rb
index 749d98ac..cd14ef23 100644
--- a/app/models/activity_pub/instance.rb
+++ b/app/models/activity_pub/instance.rb
@@ -9,7 +9,7 @@ class ActivityPub
     include AASM
 
     validates :aasm_state, presence: true, inclusion: { in: %w[paused allowed blocked] }
-    validates :hostname, uniqueness: true, hostname: true
+    validates :hostname, uniqueness: true, hostname: { allow_numeric_hostname: true }
 
     has_many :activity_pubs
     has_many :actors