System Information
Windows 10 Fall Creators Update 1709 (16299.309)
Core i7 5960x, 64Gb of RAM, GTX 1080

Blender Version
2.79.4 4f8e407

Description:
When rendering a scene and sharing the result in the Blender cloud from the menu Blender does everything and opens the browser with the cloud webpage with the image in theory, but in reality the image cannot be seen.

This is the result:

https://cloud.blender.org/p/home/5accc81c83aa13432a34abdf?t

Dr.Sybren identified the problem being the render oputput being EXR, and it being not supported by the cloud.

Exact steps for others to reproduce the error
Configure the render output as EXR
Render the scene
Upload to the cloud.

Proably it would be better if the result gets converted to PNG internally before uploading it to the cloud if the cloud does not support EXR.