A black screen can be caused by several different issues. First determine which part of the system is causing the problem.
Check whether the receiver unit (goggles) display is working normally. If the display is normal and the status bar in the lower-right corner shows Standby Mode, Low rf Power, the issue is likely related to the air unit.
Follow this guide for troubleshooting.
Check whether the receiver unit (goggles) display is working normally. If the receiver unit does not display any image at all, the issue is likely related to the receiver unit.
Follow this guide for troubleshooting.

If the issue persists after completing the troubleshooting steps above, please contact CADDXFPV official support for further assistance.