strage doorbell sound

[bejum95954]

Hi,

I'm new to this, so be considered

have A6 2.7T 2 years old
suddenly started making strange
"doorbell" sounds, but no worning lights on the diplay. I know she try to tell me something,
but what???

 

[28v6]

Lights left on perhaps, boot left open, keys left in the ignition???