User has assigned the Manager and Time & Expense subscriptions to several employees, but none of them can see the Personal Time Off feature under Time & Expenses on the main navigation.
This can happen if the security permissions of the employees restrict them from viewing the Personal Time Off Requests screen. To allow them access to PTO, you need to customize their security permissions and grant them access there. Only proper subscription isn't enough; it must be backed by proper security permissions. In particular, you need to make sure the Personal Time Off module is checked in the Security Profile of the employees. You can also customize individual security options under this module. Check the Core Help for more on customizing security permissions.