This article explains how to activate the Timerack integration in the Apex system.

1) Log into the Security Center and filter for Primary User Type: Integration Agent.  

2) You should see a new user with the above username. Double click to go into edit mode, then click on Company Access at the top.

From there, you can enable or disable the company access by marking the checkbox for that company.  If the box is not checked, you will not be able to connect to that account.