diff --git a/apps/guest-pin-codes/src/reducer.ts b/apps/guest-pin-codes/src/reducer.ts
index fb8dfe81f..944244819 100644
--- a/apps/guest-pin-codes/src/reducer.ts
+++ b/apps/guest-pin-codes/src/reducer.ts
@@ -90,8 +90,8 @@ const reducer = (
             eventId: action.payload.eventId,
             pin: action.payload.pin,
             guestNetwork: action.payload.guestNetwork,
-            start: action.payload.start,
-            end: action.payload.end,
+            start: action.payload.start.toISOString(),
+            end: action.payload.end.toISOString(),
           },
         },
         pins: state.pins.filter((pin) => pin !== action.payload.pin),