diff --git a/packages/backend/src/core/activitypub/models/ApNoteService.ts b/packages/backend/src/core/activitypub/models/ApNoteService.ts
index c6e93a0f67..b93e6e245e 100644
--- a/packages/backend/src/core/activitypub/models/ApNoteService.ts
+++ b/packages/backend/src/core/activitypub/models/ApNoteService.ts
@@ -71,7 +71,7 @@ export class ApNoteService {
 	}
 
 	@bindThis
-	public validateNote(object: IObject, uri: string) {
+	public validateNote(object: IObject, uri: string): Error | null {
 		const expectHost = this.utilityService.extractDbHost(uri);
 
 		if (object == null) {