E-flite UMX Radian and Jumper 4 in 1 Error Fix - Surprise Landing High Wire Act.
The Jumper 4in1 module was giving a "Signal Is Critical" error with the UMX Radian because the protocol was set to X-22ms (DSMX). I moved it to 2-22ms (DSM2). There may be other settings that will also work because I have not tried them all.

Music from YouTube Audio Library
"Christmas_Village"