diff --git a/src/client/response/header/mime.rs b/src/client/response/header/mime.rs
index 73044d9..d7ea2d0 100644
--- a/src/client/response/header/mime.rs
+++ b/src/client/response/header/mime.rs
@@ -28,7 +28,7 @@ impl Mime {
                 Ok(string) => Self::from_string(string.as_str()),
                 Err(_) => Err(Error::Decode),
             },
-            None => Err(Error::Undefined),
+            None => Err(Error::Protocol),
         }
     }
 
diff --git a/src/client/response/header/mime/error.rs b/src/client/response/header/mime/error.rs
index d9b19fd..989e734 100644
--- a/src/client/response/header/mime/error.rs
+++ b/src/client/response/header/mime/error.rs
@@ -1,5 +1,6 @@
 #[derive(Debug)]
 pub enum Error {
     Decode,
+    Protocol,
     Undefined,
 }