It seems there is a temporary issue between your internet provider and Digitial Ocean CDN that we use for the Metronic downloads.
In the meantime, could you please provide us with your license key from https://1.envato.market/EA4JP
Then we will send you a download link to download Metronic demos and framework versions.
We invite you to join our products community at https://devs.keenthemes.com/.
There you can get assistance and guidance from KeenThemes core developers and community members.