I can see yours on nostrgram.co but mine isn't working. Will give it a few more days.
Discussion
Your site's CORS policy doesn't allow null origins, so no web app is going to be able to access the Nip05 verification without a proxy.
If you're using apache as your web server you can add a line to the .htaccess file in the .well-known folder that allows null origins, that way the allowance is limited only to the files in that folder.