Was finally able to run Filebrowser on my Docker where setup was via Portainer Stack.

Install via Portainer:

1. Create a new stack
2. Enter the following code:

version: '3'
services:
  app:
    image: 'filebrowser/filebrowser:s6'
    container_name: filebrowser
    restart: unless-stopped
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Asia/Manila
    ports:
      - '39961:80'
    volumes:
      - /path/to/files/data:/srv #this is where the files uploaded will be saved.
      - /path/to/filebrowser/config:/database #this is where /database/filebrowser.db will be saved
      - /path/to/filebrowser/config:/config # this is where /config/settings.json will be saved