diff --git a/lib/electrumx_rpc/rpc.dart b/lib/electrumx_rpc/rpc.dart
index e32b0f967..ce733c03c 100644
--- a/lib/electrumx_rpc/rpc.dart
+++ b/lib/electrumx_rpc/rpc.dart
@@ -135,7 +135,10 @@ class JsonRPC {
       // );
     }
 
-    return req.completer.future;
+    return req.completer.future.onError(
+      (error, stackTrace) =>
+          Exception("return req.completer.future.onError: $error"),
+    );
   }
 
   void disconnect() {