thats very odd. Its below the cirrus clouds, which are still illuminated by the sun, and seem to be in the shadow of the lower cloud deck... but maybe it is illuminated by the sun. Maybe wildfire smoke? I dont know.
a sunset. The setting sun found a gap in the clouds as it sets and illuminates the underside of clouds close to your location. Here in central Texas I look for these conditions to get some really nice sunset pics in the backyard. https://www.dpreview.com/galleries/2481195021/photos/1031071/