diff --git a/src/activitypub/inbox.js b/src/activitypub/inbox.js
index 8aaa1ce279..de6c14f53f 100644
--- a/src/activitypub/inbox.js
+++ b/src/activitypub/inbox.js
@@ -98,6 +98,10 @@ inbox.announce = async (req) => {
 	} else {
 		pid = object;
 		tid = await activitypub.notes.assertTopic(0, object);
+		if (!tid) {
+			return;
+		}
+
 		await topics.updateLastPostTime(tid, timestamp);
 	}
 
diff --git a/src/activitypub/notes.js b/src/activitypub/notes.js
index 9ffb93e32e..a360198446 100644
--- a/src/activitypub/notes.js
+++ b/src/activitypub/notes.js
@@ -122,7 +122,6 @@ Notes.getParentChain = async (uid, input) => {
 				}
 			} catch (e) {
 				winston.warn(`[activitypub/notes/getParentChain] Cannot retrieve ${id}, terminating here.`);
-				chain.delete(id);
 			}
 		}
 	};
@@ -153,6 +152,10 @@ Notes.assertTopic = async (uid, id) => {
 	 */
 
 	const chain = Array.from(await Notes.getParentChain(uid, id));
+	if (!chain.length) {
+		return null;
+	}
+
 	let { pid: mainPid, tid, uid: authorId, timestamp, name, content } = chain[chain.length - 1];
 	const members = await db.isSortedSetMembers(`tid:${tid}:posts`, chain.map(p => p.pid));
 	if (tid && members.every(Boolean)) {