So the other day while working on this post I faced the issue that the map wasn’t showing as an IFrame, it was showing nothing but and empty white rectangle. This because by default nginx doesn’t allow X-Frames. In order to do this it is needed to edit file /etc/nginx/snippets/ssl-params.conf and change DENY to SAMEORIGIN as below:

grep "SAMEORI" /etc/nginx/snippets/ssl-params.conf 
add_header X-Frame-Options SAMEORIGIN;

References:
1) Nginx web
2) geekflare.com