Your .atlas file does not contain the region png/red/tors. SkeletonViewer can load the file because it ignores missing region and replaces it with a "fake" region. This is however not expected Spine Runtimes behaviour.
As a general tip to understand errors in spine-cpp and spine-cocos2d-x, please enable the Cocos2D assertions. This will ensure errors are printed onto the console:
spine-runtimes/SkeletonRenderer.cpp at 3.8
In your cause, the error is "Error reading attachment: tors", which means that attachment is missing in your atlas.
Please make sure you pack all regions into your atlas.
