As more domain extensions have been launched, it has become evident that not all software is keeping up with these new extensions.
When you submit your email address online, typcially the website will do a check to ensure the email address is valid. The check may be as simple as looking for the "@" symbol, or it may look at the domain extension to ensure it is recognized as valid. We've seen validation code that rejects email as invalid if the domain extension has more than 3 or 4 characters. Some email applications have similar limitations.
The issues are more severe for Internationalized Domain Names that include accents and non-ASCII characters such as Arabic script. The outdated checks are being updated all the time, but if you want an email address that "just works" all the time, then .com, .net, and .org are your best bets.
You will likely experience very few problems with domain extensions that contain only letters (a-z) and numbers.
Your second level domain (the part to the left of the dot) should be limited to letters, numbers, and hyphens.
