My 2009 E320 Mercedes Bluetec audio system turned mute after battery was disconnected for two weeks.
Selecting Audio a message "Device Unavailable" pop up on Command Display.
Selecting CD I can see the CD track running but no sound coming from speakers. I simply have not audio at all. It is completely mute.
Note: Mute button is not activated.
What should I do to restore my system?
Please help me on it.

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Nyck - TX - USA