Fix remote following

data/services/mastodon/nginx/mastodon.conf

@@ -75,7 +75,7 @@ location /api/v1/streaming {
     tcp_nodelay on;
   }
 
-	location ~ /.well-known {
+	location ~ /.well-known/acme-challenge {
         allow all;
 		root /var/www/html;
 	}