Cannot specify a port when configuring a new proxy host in the domain name with 2.12.1

[codethought]

Checklist

• Have you pulled and found the error with jc21/nginx-proxy-manager:latest docker image?
  • Yes
• Are you sure you're not using someone else's docker image?
  • Yes
• Have you searched for similar issues (both open and closed)?
  • Yes

Describe the bug

With version 2.12.1 the ability to specify a port in the domain name when adding a new proxy host now generates an error where it did not in 2.11.3. See attached screen shots.. If this is not a bug I would like to know how to accomplish this same thing now with newer versions. Thanks.

Nginx Proxy Manager Version

2.12.1

To Reproduce Steps to reproduce the behavior:

1. Go to Hosts | Proxy Host
2. Click on 'Add Proxy Host'
3. Try to add a host with a port in the domain name
4. See error

Expected behavior

I would expect to be able to enter a port with the domain name

Screenshots

Operating System

Docker within Unraid (Linux)

Additional context