diff --git a/packages/backend/src/core/FanoutTimelineEndpointService.ts b/packages/backend/src/core/FanoutTimelineEndpointService.ts
index 13357d3c5d..2a45b1a98b 100644
--- a/packages/backend/src/core/FanoutTimelineEndpointService.ts
+++ b/packages/backend/src/core/FanoutTimelineEndpointService.ts
@@ -32,7 +32,7 @@ type TimelineOptions = {
 	alwaysIncludeMyNotes?: boolean;
 	ignoreAuthorFromBlock?: boolean;
 	ignoreAuthorFromMute?: boolean;
-	ignoreAuthorFromInstanceBlock: boolean;
+	ignoreAuthorFromInstanceBlock?: boolean;
 	excludeNoFiles?: boolean;
 	excludeReplies?: boolean;
 	excludePureRenotes: boolean;