You have uploaded a new license file to DLP under System > Settings > General > Edit General Settings; However, Even after the license file is uploaded, the Save option on the page is still grayed out and you are unable to save the settings.
16.x
25.x
The 'Fully Qualified Manager Name' entered for the enforce contains an invalid character '_'.
Remove any special characters and rename the enforce to its FQDN, e.g.: enforceDLP25 or enforceDLP25.<domain name>.com. The save option will now be available.