diff --git a/packages/backend/src/remote/activitypub/resolver.ts b/packages/backend/src/remote/activitypub/resolver.ts
index 5f7752bd3..e972d35de 100644
--- a/packages/backend/src/remote/activitypub/resolver.ts
+++ b/packages/backend/src/remote/activitypub/resolver.ts
@@ -133,7 +133,10 @@ export default class Resolver {
 			throw new Error("invalid response");
 		}
 
-		if (object.id == null) return object;
+		if (object.id == null) {
+			throw new Error("Object has no ID");
+		}
+
 		if (finalUrl === object.id) return object;
 
 		if (new URL(finalUrl).host !== new URL(object.id).host) {