尝试升级，我认为我弄坏了什么东西

[JammyDodger]

最近有几份类似的报告称 previews 插件是旧版本，将其更新到新存储库可以解决问题：

Oops. The software powering this discussion forum encountered an unexpected problem

Could be this thing! I have this in my app.yml git clone https://github.com/merefield/discourse-topic-previews.git -b "theme_sidecar" This is obviously an old repo with a special branch! Will try with the latest one: git clone https://github.com/paviliondev/discourse-topic-previews-sidecar EDIT: It works!!! Thanks a great deal to @raghukamath