Please follow these instructions:https://wiki.jriver.com/index.php/Restoring_a_LicenseIf you have problems1) Make sure your computer is connected to the internet and is not blocked for https access to the internet (port 443).
2) Check to see if your computer's time and date are accurate.
3) Try to copy and paste the license code in as opposed to typing it. If you must type it, make sure that you distinguish between the letter O and the number 0 as well as the letter l and the number 1.
4) If you are running on a non-supported (not debian) distro, your certificate store must be correct.
On some machines you can do:
sudo update-ca-certificates
On others (ie fedora) you may need to link the existing cert file into /etc/ssl/certs:
cd /etc/ssl/certs
sudo ln -s /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem ca-certificates.crt
5) If all else fails, you can download the mjr file via
https://rover.jriver.com/cgi-bin/restore.cgi (it's good for 2 weeks) and install the license manually, using the Linux terminal (as the USER running MC, and NOT as root or sudo).
Type:
mediacenter24 /RestoreFromFile ~/Downloads/"Media Center24 Linux-YYYYYY.mjr"
(replacing Media Center24 Linux-YYYYYY.mjr" above with your filename and replacing ~/Downloads with your path).