There are several reasons why the module can be disabled:

1. When just installed it is disabled by default
2. It can be disabled by the administrator on its settings page
3. It may be automatically disabled due to some license issues, such as:
• you were using trial license and it expired
• somebody was trying to use the same license key you're using for this module on some other domain
• the license key was changed by administrator to an incorrect one

The module can be enabled from your admin section.