diff --git a/src/activitypub/notes.js b/src/activitypub/notes.js
index 1001e517a6..f3608e5c4f 100644
--- a/src/activitypub/notes.js
+++ b/src/activitypub/notes.js
@@ -158,6 +158,7 @@ Notes.assert = async (uid, input, options = { skipChecks: false }) => {
 			const followers = await activitypub.notes.getCategoryFollowers(cid);
 			// eslint-disable-next-line no-await-in-loop
 			await activitypub.send('cid', cid, followers, {
+				id: `${object.id}#activity/announce`,
 				type: 'Announce',
 				to: [`${nconf.get('url')}/category/${cid}/followers`],
 				cc: [activitypub._constants.publicAddress],