Https problem - mismatch name error

I bought a domain on OVH (1-2 days ago). I set up a redirection to my free subdomain on weebly.com (iframe). When I try to visit the site from new domain (https://), all browsers inform me that site is unsafe. I found out that this is so called common name mismatch error. What's more, new domain do not force https. How do I solve that?

https://bia-radca-prawny.eu - new domain with redirection (old domain that is redirected to ends with weebly . com instead of .eu).