Virtualmin Login from off network

For some reason when I am not on the same network as my server, I can not login to Virtualmin. When I try to access Virtualmin (https://server1.mydomain.com:10000), my browser just spins it’s wheels and then times out. However, I am able to access Usermin (https://server1.mydomain.com:20000) just fine. When I am on the same network as my server, I can login to either.

Is there a setting in Virtualmin which would cause this?