Fix mention_urls error

app/lib/activitypub/tag_manager.rb

@@ -212,4 +212,24 @@ class ActivityPub::TagManager
       []
     end
   end
+
+  def mentions_uris(status)
+    if status.account.silenced?
+      # Only notify followers if the account is locally silenced
+      account_ids = status.active_mentions.pluck(:account_id)
+      uris = status.account.followers.where(id: account_ids).each_with_object([]) do |account, result|
+        result << uri_for(account)
+        result << account_followers_url(account) if account.group?
+      end
+      uris.concat(FollowRequest.where(target_account_id: status.account_id, account_id: account_ids).each_with_object([]) do |request, result|
+        result << uri_for(request.account)
+        result << account_followers_url(request.account) if request.account.group?
+      end)
+    else
+      status.active_mentions.each_with_object([]) do |mention, result|
+        result << uri_for(mention.account)
+        result << account_followers_url(mention.account) if mention.account.group?
+      end
+    end
+  end
 end