clk 320cdi bluetooth problem

[fatjay]

hi guys just got my wife a clk on a 55 plate with sat nav it finds her iphone 6+ i put the codes in 0000 and it connect then drops the phone in 3 seconds im sure its been asked and sorted but i cant find any it finds UHI-sn3717 and then drops it not sure why but any help would be great thanks in advance Jason