Radio fails when trying to download bin over mavlink

I have a pixhawk that is controlling a homebuilt quad the vehicle is working well but when I go to download the logs using the wireless 3dr radios I get the attached error. Also as soon as I get the error the radio link drops to 4% and then disconnects.

Quadricopter X running 3.2.1
3DR Radios
Happens Everytime
Turning off the rc transmitter radio does not help
There is no problem noted sofar other than this.

thanks

you have to usb connect for logs