1. When user launches Captivate, there is a "sign in required" screen. Click on "Not your Adobe Id"
2. Now, user has to sign in with their "Enterprise Id" to which the license has been assigned. Once entered the email address, choose "Enterprise Id" and proceed further using ACC credentials.
3. Once user has signed in with the Enterprise Id, Captivate should get activated, and it should not prompt for the serial key.