Keep a copy of your current License.xml in a secure, off-server location.
Identifies if you are on Standard, Professional, or Enterprise.
Clear your web browser cache or log out and log back into the system. If the issue persists, a graceful restart of the ManageEngine ServiceDesk Plus service on your host server will force the application to reread the license parameters. Best Practices for License Management
The system clock on your server does not match the real-world date, or the license evaluation period ended.