Running Apache (with .htaccess) App Behind Nginx Rerverse Proxy – Docker

I’ve recently begun trying to Dockerize my services and I’m to the point of Dockerizing everything that already has an image built. Now I’m trying to build an image for facileManager (FM) which doesn’t yet have one. I’ve got it mostly working but I’m having an issue when running it behind Nginx. FM is normally an apache-php app and doesn’t include install instructions for Nginx. What I’ve noticed with my container/image is that it works ok when I connect directly to it through a published port but if I try to connect to it through Nginx it errors out complaining about the .htaccess file not working. I’m not an expert in either Apache or Nginx so I did my Googleing but didn’t come up with much beyond WordPress having a similar issue with it’s "pretty urls" so I’m hoping someone here can give a hand.

First here is the Github repo for the app: https://github.com/WillyXJ/facileManager/tree/ea159f5f6112727de8422c552aa05b6682aa4d79/server

The .htaccess file specifically is:

<IfModule mod_headers.c>
    <FilesMatch ".(js|css|txt)$">
        Header set Cache-Control "max-age=7200"
    </FilesMatch>
    <FilesMatch ".(jpe?g|png|gif|ico)$">
        Header set Cache-Control "max-age=2592000"
    </FilesMatch>
</IfModule>

<IfModule mod_rewrite.c>
RewriteEngine On

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php [L]
</IfModule>

The exact error I’m getting is from here:
https://github.com/WillyXJ/facileManager/blob/ea159f5f6112727de8422c552aa05b6682aa4d79/server/fm-includes/init.php#L153

if (!defined('INSTALL')) {
        if (@dns_get_record($_SERVER['SERVER_NAME'], DNS_A + DNS_AAAA)) {
            $test_output = getPostData($GLOBALS['FM_URL'] . 'admin-accounts.php?verify', array('module_type' => 'CLIENT'));
            $test_output = isSerialized($test_output) ? unserialize($test_output) : $test_output;
            if (strpos($test_output, 'Account is not found.') === false) {
                $message = sprintf(_('The required .htaccess file appears to not work with your Apache configuration which is required by %1s. '
                        . 'AllowOverride None in your configuration may be blocking the use of .htaccess or %s is not resolvable.'),
                        $fm_name, $_SERVER['SERVER_NAME']);
                if ($single_check) {
                    bailOut($message);
                } else {
                    $requirement_check .= displayProgress(_('Test Rewrites'), false, 'display', $message);
                    $error = true;
                }
            } else {
                if (!$single_check) $requirement_check .= displayProgress(_('Test Rewrites'), true, 'display');
            }
        }
    }

Nginx config:

server {
        listen 80;

        server_tokens off;

        location /.well-known/acme-challenge/ {
                root /var/www/certbot;
        }

        location / {
                return 301 https://$host$request_uri;
        }
}

server {
        listen 443 ssl;

        server_name bound.example.com;

        ssl_certificate /etc/nginx/ssl/live/bound.example.com/fullchain.pem;
        ssl_certificate_key /etc/nginx/ssl/live/bound.example.com/privkey.pem;
        include /etc/nginx/ssl/options-ssl-nginx.conf;
        ssl_dhparam /etc/nginx/ssl/ssl-dhparams.pem;

        location / {
                proxy_pass http://FM.;     <<< Docker service name
                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
                proxy_set_header Host $host;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
        }
}

My Dockerfile/commands run: https://github.com/MeCJay12/facileManager-docker

FROM php:7.4-apache

ENV TZ=UTC
ENV Version=4.2.0
ARG DEBIAN_FRONTEND=noninteractive
WORKDIR /src

RUN apt-get update 
    && apt-get -qqy install wget libldb-dev libldap2-dev tzdata 
    && wget http://www.facilemanager.com/download/facilemanager-complete-$Version.tar.gz 
    && tar -xvf facilemanager-complete-$Version.tar.gz 
    && mv facileManager/server/* /var/www/html/

RUN ln -s /usr/lib/x86_64-linux-gnu/libldap.so /usr/lib/libldap.so 
    && docker-php-ext-install mysqli ldap 
    && a2enmod rewrite dump_io

COPY php.ini /usr/local/etc/php/php.ini
RUN rm -r /src

Bonus question: When accessing this container/image directly through a published port, the images are all broken. I assume it’s related since the .htaccess file includes references to images files.

Thanks in advance for the help!