security warning for alias domains

Hi

I have a single website hosted on your servers which is set up with an SSL certificate. However I have an issue with alias domains (which used to be parked?) - when people try to reach the site via one of the aliases, they receive a message saying the site is unsafe. If they continue, then they reach the final website through the redirection. I don't know how to resolve this issue.

Thank you in advance for your help

Julie