If you have LetsEncrypt installed on your website and you add a new domain pointer/alias you may run into SSL issues with the newly pointed domain.
An SSL certificate is not automatically assigned to the new domain that you are pointing as the LetsEncrypt routine is not run when you add an alias/pointer.
Firstly, if you have enabled Force SSL in anyway you need to disable it by whatever means you have enabled it.
Then to resolve this issue please go to the SSL tab under the website in the CP.
- Click Delete Certificate.
- Wait for it to uninstall.
- Now install a new LetsEncrypt certificate.
- Assuming that is successful you can now re-enable Force SSL if you disabled it above.
Now all your websites hostnames including the new pointers/aliases have certificates issued and bound to the website.