diff --git a/content/jwt.xqm b/content/jwt.xqm
index 9c61ccf..61a9b6b 100644
--- a/content/jwt.xqm
+++ b/content/jwt.xqm
@@ -81,7 +81,7 @@ declare function jwt:read ($token as xs:string, $secret as xs:string, $lifetime
                 then (error(xs:QName("future-date"), $dt, jwt:epoch-to-dateTime($payload?iat)))
                 else ($payload)
         )    
-        else (error())
+        else (error("invalid-signature"))
 };
 
 declare function jwt:sign ($data as xs:string, $secret as xs:string) as xs:string {