Taxonomy panel not visible

Hello!
I am writing a plugin and using custom post type and custom taxonomy. When writing a plugin, I tested it
on localhost. When I opened a post with a custom post type for editing, the taxonomy panel was displayed in the sidebar of the block editor.
Then I started testing the plugin on a real hosting – and when I opened a post with a custom post type for editing, the taxonomy panel on the sidebar of the block editor is not displayed. If you reload the page several times, sometimes the taxonomy panel is visible.
Why is this taxonomy panel not visible? What to do?

I did as recommended – first register the taxonomy, and then the post type with which this taxonomy is associated:

register_taxonomy( ... );
register_post_type( ... );

and set the parameter show_in_rest = true to make the taxonomy panel appear in the sidebar of the block editor.