Hi @angus ,
Thank you so much for your reply. I do notice several red lines in the console, please see the picture below from Opera whenever I entered to a post.
It looks like there is something wrong at “import” in my installation. I install Discourse using source code, not Docker, therefore I always put new plugins into discourse/plugins, by which I successfully installed another two plugins. I am not sure if it was the proper way to have retort installed in the same way.
By the way, I did have
@popperjs/core installed using npm before, but I don’t know why I encountered this error…