Deploying rancher/hello-world cannot select port 80

Question

I am new to Rancher, trying to deploy the rancher/hello-world example with following steps:

1. Oracle VirtualBox and Ubuntu 20.04 with Rancher docker installed
2. sudo docker run --privileged -d --restart=unless-stopped -p 80:80 -p 443:443 rancher/rancher
3. Following tutorial on Rancher to deploy Rancher/hello-world (https://rancher.com/docs/rancher/v2.6/en/quick-start-guide/workload/quickstart-deploy-workload-ingress/)
4. At step 9 of “Expose The Application Via An Ingress”, I cannot select port 80 (port 443 is the only available port to select).

How can I proceed? Thanks.