When you're creating a new web application, you may encounter the following error:
New-SPWebApplication : http://contoso.com is already routed to the Default zone of another application. Remove that mapping or use a different URL
Usually this occurs when you have deleted a web application and immediately trying to create another web application with the same name. The timer service has not had a chance to execute the admin jobs to clear out all the settings in the configuration database.
To expedite the timer job you can run this PowerShell command:
Stop-Service -Name SPAdminV4
Start-Service -Name SPAdminV4