In some rare cases when activating TextMiner panel in Outlook you may see the error message:
The token is not valid after MM/DD/YYYY hh:mm:ss
When Outlook client is opened for a very long time it may not automatically renew the security token.
Restart desktop Outlook or the browser (whatever client you use) and re-login. The email client will provide TextMiner with a valid token and no license error message will be shown afterwards.