If you have more than one camera connected to your computer, you'll need to choose one as your default camera for Google Chrome.
Setting your default camera
1. Click the three dots ( ) on the top right corner and select Settings
2. Select Privacy and security
3. Select Site Settings
4. Click Camera
5. Select a camera from the menu
(If there is only one option when you click the menu, then your computer only has one camera)
For more help with camera permissions, read My camera isn't working in Google Chrome.