Kotlin Koans with EduTools plugin: "Failed to launch checking"

Question

I'm trying to follow the Kotlin Koans tutorial in Android Studio by installing the EduTools plugin and choosing Kotlin Koans course.

Everything works fine, but when I try "Check Task" in the Task Description panel, I get this error:

Failed to launch checking

I also tried the plugin with Intellij IDEA and got the same error.

Using:

• Android Studio 3.2 with EduTools 2.0-2018.1-443
• Intellij IDEA 2018.2.3 with EduTools 2.0-2018.2-906