I've setup Wordpress Multisite on an Amazon Web Server EC2 instance. I'm using an Elastic IP and a Load Balancer on the instance. I have setup a wildcard SSL certificate for the Multisite through AWS Certificate Manager, which works for the main site and all new subdomain websites created. I applied this certificate to the load balancer.
Now I am trying to setup an SSL certificate for a mapped domain. I have the domain bought through Namecheap and have setup an A Record to the Elastic IP. I also created an AWS Certificate and validated it through a CNAME record on the Namecheap DNS. I applied this certificate to the same Load Balancer and I setup a Route 53 for the subdomain in AWS that I pointed to the Load Balancer.
The domain mapping works as I have gotten newsite.com to show the content on newsite.multisite.com without showing the subdomain URL. However, the SSL certificate defaulted to the Bitnami default SSL which is obviously unsecure:
I am using the Really Simple SSL plugin to activate the SSL certificate on my websites. Any ideas on how to get this working?