If the Set Temp Password link does not appear, this is likely because the user is LDAP enabled.

To check your LDAP enabled roles, navigate to:
  1. Core > Security > LDAP Authentication.
  2. If "Enable LDAP" is marked, then you have users that are LDAP Authenticated.
  3. Scroll through the roles to see which are enabled:

If the user's role is LDAP enabled, the user's password must be reset on the LDAP server by your IT department.

Read more about LDAP 

This could also be caused by the Account being Temporarily Disabled/Locked.

To see if a Users Account is Disabled/Locked, navigate to:
  1. Navigate to Core
  2. Using People Finder, search for the preferred user> Select the user
  3. Select the Access tab
  4. Within the Log In Information section, review the Disabled/Locked section to verify the status of the account.