The use of Timerack's Email Timesheet Approval feature requires that an email recipient, "Approver Email," be designated on each Assignment record in the portal. The approver email address can be populated manually in Timerack or via integration.  Click here to view the TempWorks Knowledge Base article on how to utilize Order Contact Roles to designate an "External Timeclock Approver," which will populate the Approver Email field on the related Assignment(s) in the Timerack portal.