Nothing happens

I found existing topics about this, but there was no answer :/ I Installed the plugin, made the needed settings, but when I click on the sidebar button, nothing happens besides redirect with the given URL:

https://########/wp-admin/post.php?post=1201&action=edit&shippint_add_print=true&print_url=http%3A%2F%2Fjavas.dev%2Fwp-admin%2Fadmin-ajax.php%3Faction%3Dbulk_shipping_print%26ids%3D1201

I dont think a screenshot is needed, since literally nothing happens, just a page refresh with the url. No console log, or network problem logged ?? Any idea?