You may see the following error message on attempt to create new web application using SharePoint 2013 CA UI:
Error message says: “Invalid URI: The hostname could not be parsed“, at the same time creation of web application using PowerShell may work just fine. This error can be caused by the fact that you have asterisk (“*”) as a value of Host name property in bindings of one of your existing web applications. Removing asterisk and leaving host name blank should resolve this issue.