NEED HELP esc or receiver?

[dexcrawler]

I HAVE SPEAKTRUM DX3E WORK WITH BR-XL,WHEN I WAS PLUGED THR AND STR THAT SERVO AND MOTOR WORKS FINE.BUT CAN NOT WORK WITH AUX WHEN PLUGED DIG SERVO.THE LED LIGHT FLASH ALL TIME ON RECEIVER AND NO RESPONSE.BUTI TAKEN OFF AUX PLUG,EVERYTHING BACK TO NORMAL.I WAS TRY TO TAKEN OFF STR SERVO AND PLUGED INTO AUX,THAT WORK SUCCESSFUL ON AUX THEN PLUGED DIG SERVO INTO STR,DEAD TOO..I ALSO SETUP "NO CUTOFF VLOATAGE" IS YES ON ESC.I HAVE Try TWO BRAND NEW SERVOS,NOTHING CHANGE.
THE BATEERY IS 1600 MA 7.2V Ni-MH

ANY SUGGESTION PLEASE..