Nginx (Reserve Proxy) + (Apache + Nextcloud) which server handle mime js mjs

2 questions, which server handle the mjs , other is work on LAN/WAN

I am newbie on Nextcloud v28. Now have 3 premise servers, Nginx as reserve proxy, proxy pass https to apache/nextcloud and onlyoffice server.

On nextcloud admin section , the loggin and additional setting is blank page only , no header , no any text

On forum claim add the mjs at mime.type, that I have some confuse, Nginx is handle the front end traffic and Apache/Nextcloud handle backend , look like both will has chance handle the mime.type , During this situation, should which server handle mime?

Another is I test Nextcloud access with FQDN https with onlyoffice. Now all seem work fine. But when I get the local subnet access will have problem. Get the https error due to access local ip and due to onlyoffice need serve with WAN users, I need put onlyoffice listen on WAN port. When user access Nextloud with local IP will have certificate untrust issue. I can force all user use FQDN access but on nextwork side not too make sense cause server in local subnet but need go out wan, through FQDN go back local server, any good documents or sample override this issue.

If you’re using Apache as the web server it probably isn’t cause by .mjs handling. It’s more likely your web browser’s ad blocker extension.