Photoshop’s 3D features will be removed in future updates. Users working with 3D are encouraged to explore Adobe’s new Substance 3D collection, which represents the next generation of 3D tools from Adobe.
Additional details on the discontinuation of Photoshop’s 3D features can be found here: Photoshop 3D | Common questions around discontinued 3D features.
When using Photoshop CC 19.1.1 or earlier and you select 3D > Share 3D Layer On Sketchfab... you encounter a 413 error or you get a broken URL or white page after upload.
When using Photoshop CC 19.1.2 or later the Share 3D Layer On Sketchfab... command is no longer available.
This feature is no longer being developed or supported.
Export your 3D content and upload it directly through the Sketchfab website: http://sketchfab.com