This is quite a common situation, and the main thing here is to create a comfortable atmosphere. Many girls are simply afraid that they will be recorded or judged for their appearance. So it's better not to insist, but to give her time to get used to socializing. I use
videocamchat because there are less fakes and more people ready for open communication. You can start with the camera turned on yourself, talk casually, make jokes, create trust - and then the chance that the girl will also turn on the video, increases.