I am only taking a guess because no one else has.
But you need to check the exposure time, my guess is, that if you have 2 clicks, it is the shutter opening and then the shutter closing.
I am not sure what all can be changed in auto mode, so this is all a guess.....perhaps the ISo is too low or you have dialed in some minus exposure compensation. Examine the exif with an exif reader such as opanda or kuso and check the shuttter speed.
If at one time it took nice photos indoors ,I would guess something has been changed.........perhaps a reset to factory settings
Gene from Western Pa
D50 ....D80.....D7000 - 18 to 200VR- 50mm 1.8 - 80 to 400 OS
Just trying to learn and it's slow going!