Kakute F7 AIO S.Port Telemetry

I have a kakute f7 AIO with an XSR receiver and yappu telemetry with S port and 4.0.2 arducopter firmware . My problem is when i conect the battery and start the initaliazation works normal but after 2 minutes i have “sensor loss” error and lost telemetry. When i reconect the battery again telemetry is not working at all. Why is this happening???