Just upgraded and also migrated to a new server, mysql 8 (disabled strict mode) and php 7.3
It seems some users get the attached pop-up when attempting to reply to a topic.
Does anyone know the reason? Does vanilla not support mysql 8?
Ok so this happened because all the roles were set to an account. So setting just 2-3 fixed this.
And now it's time to hide in shame - I forgot to do /utility/update.
You can delete this thread. Sorry.