What Causes Bad Odour In Between The Thighs?

Hi I have a weird old smelling odor in the crease of the thighs for a while now . I originally thought it was from not washing correctly but I m a very clean person. It still happens mostly in the morning. But it s weird because when I shower at night , I go right to bed and wake up with this odor. Went to a gyno and no answers . Please help!!!!