Cause

Adobe CC only allows users you activate two devices simultaneously. Each AWS Appstream session started by a person will create a different computer, which will have different computer hardware information.

Solution

1. Select "Sign out" under either computer name, as noted in Fig.1. The preferred choice is a computer name that starts EC2AMAZ-, which would be your last AWS Appstream session.

2. When you are signed out of the other device, click Continue, as seen in Fig.2