diff --git a/packages/backend/src/server/ActivityPubServerService.ts b/packages/backend/src/server/ActivityPubServerService.ts
index 54ffeecc6b..5d9ce78793 100644
--- a/packages/backend/src/server/ActivityPubServerService.ts
+++ b/packages/backend/src/server/ActivityPubServerService.ts
@@ -30,9 +30,9 @@ import { bindThis } from '@/decorators.js';
 import { IActivity } from '@/core/activitypub/type.js';
 import { isQuote, isRenote } from '@/misc/is-renote.js';
 import * as Acct from '@/misc/acct.js';
+import { FanoutTimelineEndpointService } from '@/core/FanoutTimelineEndpointService.js';
 import type { FastifyInstance, FastifyRequest, FastifyReply, FastifyPluginOptions, FastifyBodyParser } from 'fastify';
 import type { FindOptionsWhere } from 'typeorm';
-import { FanoutTimelineEndpointService } from '@/core/FanoutTimelineEndpointService.js';
 
 const ACTIVITY_JSON = 'application/activity+json; charset=utf-8';
 const LD_JSON = 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"; charset=utf-8';
@@ -131,6 +131,7 @@ export class ActivityPubServerService {
 		if (signature.params.headers.indexOf('digest') === -1) {
 			// Digest not found.
 			reply.code(401);
+			return;
 		} else {
 			const digest = request.headers.digest;