Hello!
I have lately some issues with WP Discourse, when trying to edit a post which has been already posted to Discourse, I try to add some custom fields to the post but when I hit Update, it won’t do it and I receive the message “Updating failed. Could not update the meta value of discourse_post_id in database.”
This error is gone when I disable WP discourse.
This is a generic Wordpress error indicating an issue with your Wordpress installation, that could be caused by a number of things, ranging from an issue with your database, to your caching solution, to some buggy code you have in your theme or some other plugin. It’s the same reason you’re experiencing this issue
While we can help you with the plugin, the cause of this is an issue with your Wordpress environment, and probably needs a close professional assessment of the real environment.
The confluence of this issue and your other issue, is suggesting to me the most likely cause is that you’re using a significantly out of date version of MySQL in production. But this is just a guess as I don’t have access to your environment.