A license invalid error means that a domain or IP which has not been registered with your license key has attempted to access the panel. If you have recently moved servers or updated your domain/IP then you will need to reissue your license.
Your license can be reissued from your client area, in the services section.
1. Login to your client area at https://www.mediacp.net/portal/
2. Click on My License
3. Select the license you would like to reissue
4. Click Reissue license button on this page
5. The next time you access the MediaCP, the domain and ip address will be locked into the system until you reissue again
