X-T20 image too dark

[Freshmaker]

My image is too dark at 1/15 f5.0 800iso in a brightly lit room, I compared it to an image from another user's x-t20 that's 1/35 f5 640iso and it's normal. My image should be even brighter but it's very dim. Only when I open aperture to max 2.8 and ss to 1/20 or lower and at least 800 iso will it look properly exposed. Is something wrong with my x-t20?

Edited June 3, 2017 by Freshmaker

[etomcat]

Make sure you have not dialled in exposure compensation ( although you would notice it). What mettering mode are you using? That could happen if you have used point metering with lock to focus point activated and you have focussed on a bright object. It is obvious, but you have no polarizer filter attached? Lastly, try resetting the camera.