同じユーザー名またはグループ名で複数のユーザーが投稿していますか？

[ondrej]

No worries. If you are self hosted have a look at this guide

Install plugins on a self-hosted site

This guide assumes that you have a self-hosted standard installation. We only support the standard method of install here, so these instructions assume you have a standard install. This guide only applies to self-hosted Discourse instances. If you are using a managed hosting service, the available plugins are controlled by your hosting provider. For example, on our hosting these specific plugins are available by hosting tier. In this tutorial, we’ll install the Discours…