diff --git a/app/validators/namespace_validator.rb b/app/validators/namespace_validator.rb
index 7a35958cc5f494eb2fd6db9ade91549e046d5f51..4dc3b2ab9a0df92421dba05d24fbf1b9f392cf8e 100644
--- a/app/validators/namespace_validator.rb
+++ b/app/validators/namespace_validator.rb
@@ -5,7 +5,8 @@
 # Values are checked for formatting and exclusion from a list of reserved path
 # names.
 class NamespaceValidator < ActiveModel::EachValidator
-  RESERVED = %w(
+  RESERVED = %w[
+    .well-known
     admin
     all
     assets
@@ -31,7 +32,7 @@ class NamespaceValidator < ActiveModel::EachValidator
     u
     unsubscribes
     users
-  ).freeze
+  ].freeze
 
   def validate_each(record, attribute, value)
     unless value =~ Gitlab::Regex.namespace_regex