This action does not use an Active Directory domain controller
or any other server. It only searches for an "@" character in the
userPrincipalName and verifies that the string after that
character matches one of the uPNSuffixes. The following
example would succeed because the suffix of the UPN,
"tailspintoys.com", is in the list of valid UPN suffixes.
<executeData>
<userPrincipalName>user1@domain.com</userPrincipalName>
<uPNSuffixes>
<value>domain.com</value>
<value>domain.net</value>
<uPNSuffixes>
</executeData>