diff --git a/backend-spring/src/main/java/com/erp/tenant/ReservedSubdomains.java b/backend-spring/src/main/java/com/erp/tenant/ReservedSubdomains.java
index 7905c95b..76418736 100644
--- a/backend-spring/src/main/java/com/erp/tenant/ReservedSubdomains.java
+++ b/backend-spring/src/main/java/com/erp/tenant/ReservedSubdomains.java
@@ -6,7 +6,7 @@ public final class ReservedSubdomains {
 
     public static final Set<String> VALUES = Set.of(
             "www", "admin", "api", "app", "static", "assets",
-            "main", "mail", "blog", "dev", "test", "staging", "prod", "console",
+            "main", "mail", "blog", "test", "staging", "prod", "console",
             "solution"
     );
 
diff --git a/frontend/lib/tenant/subdomain.ts b/frontend/lib/tenant/subdomain.ts
index c0de0dab..96f2d46a 100644
--- a/frontend/lib/tenant/subdomain.ts
+++ b/frontend/lib/tenant/subdomain.ts
@@ -16,7 +16,6 @@ const RESERVED_MAIN = new Set([
   "main",
   "mail",
   "blog",
-  "dev",
   "test",
   "staging",
   "prod",