Playground does not work on my environment

[Arkkimaagi]

Any suggestions how I could fix my environment to get the playground working?

I ran the example code (by clicking the top play button) and got this as a result. (I edited out my username from the screenshot)

Sketch Version 50.2 33047
Plugin version 0.6.0

[mathieudutour]

hum what's your macOS version?

[Arkkimaagi]

MacOS Sierra 10.12.6