diff --git a/src/Functions.php b/src/Functions.php
index 458dd73..8ef3e66 100644
--- a/src/Functions.php
+++ b/src/Functions.php
@@ -193,6 +193,6 @@ public static function isBackportCall($backtrace, $depth)
 
     public static function isRetrofitResource($imap)
     {
-        return is_resource($imap) && get_resource_type($imap) == 'imap';
+        return  get_class($imap) == 'IMAP\Connection';
     }
 }