Https Not working for my mapped subsites on my multi-site

I want to use https on my subsites which i mapped but it doesn't work. When i change the mapping to https or force a page to show ssl it gives the following error:

This site can’t provide a secure connection

http://www.betafood.com.ng uses an unsupported protocol.
ERR_SSL_VERSION_OR_CIPHER_MISMATCH

What could be the problem?