If you receive these errors displayed on the camera screen of the streaming device, that means another device is trying to view the camera livestream of this device but cannot because the access is denied. Each device has a unique password / secret token, which is random generated on-device and is used to authenticate the streaming request. Only registered devices listed in the Device screen can view the camera livestream. All devices signed in with the same iCloud account will automatically be registered and listed in the Device screen.
You may have a same device listed twice in the Device screen. This can happen if you delete the AiCam app and reinstall it. Then the old duplicated entry (device) will not be able to view the streaming. Please go to Device screen and run the task "Clean up duplicated entries" placed at the bottom of the screen. You can also manually delete the duplicated device by tapping on the red x-mark icon.
You may want to compare the device ID (after the # icon in the Device screen) on both the viewer and camera devices. A same physical device should have the same ID.
See this FAQ to learn more how secure is livestreaming.