diff --git a/src/Server.hs b/src/Server.hs
index 7ff1de3..976d463 100644
--- a/src/Server.hs
+++ b/src/Server.hs
@@ -200,8 +200,8 @@ instance FromHttpApiData AuthFlow where
 
 instance FromForm ClientData where
   fromForm f = ClientData
-    <$> ((parseUnique @AuthFlow "grant_type" f) *> ((Left . ACode <$> parseUnique "code" f)
-                                                <|> (Right <$> parseUnique "refresh_token" f)))
+    <$> (((parseUnique @AuthFlow "grant_type" f) *> (Left . ACode <$> parseUnique "code" f))
+     <|> ((parseUnique @String "refresh_token" f) *> (Right <$> parseUnique "refresh_token" f)))
     <*> parseMaybe "client_id" f
     <*> parseMaybe "client_secret" f
     <*> parseMaybe "redirect_uri" f