Strings formed with characters from A to Z (uppercase or lowercase), digits from 0 to 9, !, #, $, %, &, \', *, +, -, /,_Text=, ...

Strings formed with characters from A to Z (uppercase or lowercase), digits from 0 to 9, !, #, $, %, &, \', *, +, -, /,_Text=, ?, ^, _, `, {{, |, }} or ~. One or more periods may be embedded in an alias, but each period should be preceded and followed by at least one of the other characters. Unicode characters from U+00A1 to U+00FF are also valid in an alias, but they will be mapped to a best-fit US-ASCII string in the email address, which is generated from such an alias.