diff --git a/BeReadyBackend/Validators/Messages/CreateMessageDtoValidator.cs b/BeReadyBackend/Validators/Messages/CreateMessageDtoValidator.cs
index 3b95c60..2d29f8f 100644
--- a/BeReadyBackend/Validators/Messages/CreateMessageDtoValidator.cs
+++ b/BeReadyBackend/Validators/Messages/CreateMessageDtoValidator.cs
@@ -22,6 +22,8 @@ public class CreateMessageDtoValidator : Validator<CreateMessageDto>
 
         RuleFor(x => x.GroupId)
             .NotEmpty()
-            .WithMessage("GroupId is required");
+            .WithMessage("GroupId is required")
+            .GreaterThan(0)
+            .WithMessage("GroupId must be greater than 0");
     }
 }
\ No newline at end of file