Reply To: Your main plugin "meta-box" ignore language settings in WP

And meta-box plugin is active?

Here the same screenshot from clean wp install (5.0), where I have setup czech language: https://www.dropbox.com/s/js34h3vdupxuyxz/quotes-default-wp.png

And this, with meta-box plugin installed and activated: https://www.dropbox.com/s/8epzbtx9tknawt0/quotes-metabox.png