Found on their website:
Please be aware that our services are unavailable for residents of Afghanistan, Angola, Burundi, the Central African Republic, Cote d’Ivoire, Crimea, Cuba, the Democratic People’s Republic of Korea, the Democratic Republic of Congo, Eritrea, Iran, Iraq, Kosovo, Liberia, Libya, Myanmar, Palestine, Sierra Leone, Somalia, South Sudan, Sudan, Syria, United States of America*, Yemen, and Zimbabwe.

*the services are unavailable both for residents and citizens of the country.