If you are trying to login to your Stretto client and you see a Licence prompt with no Licence entered this probably indicates that the machine your running Stretto on does not have the appropriate root certificate - As a result it can not reach the provisioning server, and so can not get the licence for your Stretto client. This is not actually a problem with your licence, its an issue with the way Windows handles obtaining root certificates.
To get around this, you will just need to navigate to https://stretto.cloudprovisioning.com/status in an Internet Explorer web browser - this will prompt Windows to grab the correct root certificate and should resolve the issue.
Please note, you must use Internet Explorer. Using another browser will not work.