VOLVO 2016 I shift issue

2016 - VOLVO D13 - iShift Error >"Transmission LOW Air Supply" - comes as I’m driving

if I keep driving message shows up “transmission system failure”

also getting the error on dash > "check the transmission at the next stop"and Red stop sign on comes on and truck wouldn’t shift. Turn off and on again it’s back to normal until the “transmission low air supply” light comes on again.

checked diagnostics it shows “p107538”