Port-forwarding other than 8080:80 does not work

[toshohirasawa]

I can successfully set port forwarding from 80 (container) to 8080 (host) but failed to use ports other than 8080 as the host port.
Once I set ports like 8081:80, my Chrome says, "This site can’t be reached" when I access http://localhost:8081/.

OS: macOS 14.4.1
Rancher Desktop: 1.13.1
Kubernetes: 1.29.4

Settings changed from default:

• Virtual Machine Type: VZ
• Mount Type: virtiofs

Here is the docker-compose.yml I used:

version: '3'
services:
  dokuwiki:
    image: lscr.io/linuxserver/dokuwiki:latest
    container_name: dokuwiki
    environment:
      - PUID=1000
      - PGID=1000
    volumes:
      - './persist:/config'
    ports:
      - 8081:80
    restart: unless-stopped

I'm not sure whether the Docker image or Rancher desktop caused the problem, and I don't know how to distinguish the cause.
Any advice will be appreciated.
Thanks!