diff --git a/core/auth/errors.go b/core/auth/errors.go
index 2732b25b..3b55644b 100644
--- a/core/auth/errors.go
+++ b/core/auth/errors.go
@@ -2,7 +2,7 @@ package auth
 
 const (
 	AuthenticationError      = "User authentication error"
-	InvalidSignatureFormat   = "Invalid Signature Format"
+	InvalidSignatureFormat   = "Unable to decode client's signature. Please check the message's format."
 	InvalidAuthenticationKey = "User Auth key is invalid"
 	InvalidAPIKey            = "API key is invalid"
 	MalformedExpirationTime  = "Malformed Expired Time"