A notify rule is set to use a pager e-mail. The Current Contact (for To, Cc or Bcc) and any checked workers in These Workers (also for To, Cc or Bcc) fail to send email notifications. However, users that are manually entered in These Addresses do receive email.
This has been identified as a product defect in Helpdesk 6.0. The solution is to upgrade to the latest ticket system offered by Symantec, which is ServiceDesk 7.x.
Workarounds are available. These include:
Change the template type from a pager e-mail to a Send -email (standard e-mail template).
Or, instead of using Current Contact or These Workers, manually enter all recipient's email addresses into the These Addresses field.