You will need internet access in order to see the IP camera from outside your own WIFI. In order to get to the camera over the internet, your actual IP address is used.
When you set up the phone app, your IP address was obtained by one of several methods. Use of a DNS service, entering your IP address, or the app used your connected IP address.
When you connect from the outside over OpenVPN on your phone, the the data will be encrypted between your phone and the VPN server so over a non-secure WIFI it would be secure.
Not sure how it is working without an open port. Use a tool like http://www.canyouseeme.org/ to see if the camera port is open.

Let us know if this helps.

CanYouSeeMe did not find any open ports. I also tried Nmap with linux and also did not see any ports on the camera IP. The parental control works if I block my phone but not with the camara. Using my network, I can connect to the camera with http and RTSP, I still want to block this Vstarcam camera from the internet and use the phone app only at home. I currently use OpenVpn to connect to 2 RaspberryPi. Any help is appreciated.

1.You Chose Forwarding -->Virtual Server and check port opening 2. check config on phone app or the RTSP link