This information will help you utilize a domain name that contains an international character like "Ñ" for example.
The letter Ñ may be used in internationalized domain names, but it will have to be converted from Unicode to ASCII using punycode during the registration process (i.e. from www.piñata.com to www.xn--piata-pta.com) -Wikipedia
The internet's DNS system currently only supports ASCII characters. To use that character, you will need to use punycode to convert it to ASCII. Enter the domain name(with the special character ñ) in the following link:
IDN Conversion Tool
Then you can add the result in your WHM or cPanel. -cPanel Forums