Creating 360 images using apps and getting an error

I've tried creating 360 images using Microsoft Pix, Google Street View and 360 Panorama apps but they are all generating the error "This image might not render correctly.  For the best results, use a 360 image with a 2:1 aspect ratio".  The image looks great at first but gets distorted (fish bowl effect) in Storyline 360.  What am I missing?