HTTPS follows different rules in DirectAdmin. When you change your domain settings, you can choose to share "public_html" with non-HTTPS or you can use "private_html" only for HTTPS. Using the second option will cause the issue you see.
But, there is a bigger problem.
x10hosting free does not allow you to upload a certificate. Without a certificate, your domain will fall back to x10's certificate, which is not valid for your website; it is only valid for x10's website.
Look at using a service such as CloudFlare. CloudFlare must be set up in "flexible" mode to work.