If you enter the field validation formula
validateAddress := @ValidateInternetAddress([Address821]; User_Address);
@If(validateAddress != ""; @Failure(validateAddress); @Success)
the validation formula returns an empty string indicating a successful validation.
However if you enter
"Streitfeld, Sara (Miami)" <SStreitfeld@gazette.com>
the validation formula returns the following error message:
"Invalid RFC821 syntax, no Phrase required."