>>1545126caliper style brakes?
if so, there should be a small arm on the brakes (black lever in attached image)
this can be rotated to slack the cable cable and allow removal of the wheel. up position is slack down position is tight.
perhaps this was previously slacked.
brakes should be adjusted so there is no drag with the lever down.
fine adjustments can be made with the barrel brake handlever. larger adjustments may require loosening the cable at the caliper.
if it is only "dragging", you can probably get away with just fiddling with the barrels.
turn barrel CCW to loosen barrel and tighten cable. in your case, turn barrel CW to tighten barrel and loosen cable.