Cannot create a new account with package that uses a dedicated IP address

Symptoms

You try to create a new account in Home » Account Functions » Create a New Account and encounter this error:

Account Creation Status: failed

Your system has run out of available IP addresses, or you do not have permission to use any more IP addresses. (Unable to find an IP address.)

Description 

This error appears when you try to assign a package that uses a dedicated IP address to the account, and you only have a single IP address on the server that is already in use by other accounts.

Workaround

Assign a package that does not use a dedicated IP address.