Hello,
this is an issue with the install of your SSL and not and abantecart issue. The place to resolve this is with your host.
Is this perhaps a shared SSL? If so, strongly recommend you use a SSL issued only to your domain name. You can obtain these for $10/yr and upwards. You will also need to have a dedicated IP address from your host for your dedicated SSL.
There are lots of posts on the forum regarding ssl certs and shared certs
If this is not a shared SSL - then your host needs to correct the installation of the SSL for you to operate correctly.
This is an issue to be resolved with your host and the SSL installation.
Hope this helps
Lee