Mercedes Benz NTG4.5 comand pin spec

Hello,

I own a 2013 Mercedes E Class E250 CDI W212 RHD fitted with the NTG4.5 COMAND online navigation and I need to fix the AUX Audio input prior to upgrading to the big screen Android. I bought this car from the UK.
In the center console, between the driver and co-driver seats, there are one USB socket, which works perfectly well and an MMI socket for AUX connection.
I bought the Mercedes cable adapter, part No. A003 827 03 04, for connection to the MMI socket. I went into the Engineering Mode of COMAND online and energized the AUX function. Unfortunately, no sound is transmitted to the radio speakers using this AUX cable connection through the MMI socket, although AUX is selected on the COMAND on line. When AUX on COMAND on line is selected only “TA” can be selected and nothing else.
I tried through the MEDIA but no AUX exists there.
Can you please help?