imgur is temporarily over capacity. Please try again later is an issue on imgurs end. The plugin just sends the image and if it errors shows it in the composer.
NodeBB a friendly to SEO?
Probably I can list a lot more from the minuses, but there is also a plus, this is a good structure for SEO.
NodeBB have a settings for optimisation SEO and plugin for rating topic with schema?
I've heard that NodeBB is a good alternative, with some sweet features for optimizing your SEO.