Installing local Graphileon App (also Electron based) in Desktop 1.1.8 fails, getting error

We are trying to install a Graphileon App (located at /Applications/ on a Mac) on Neo4j Desktop 1.1.8 We get an error:

"An error occurred while processing Graph Application Graphileon. Cannot resolve graph app type. Please check your internet connection or Graph App link."

We can run it independently from Neo4j Desktop / and connect to stores without any problem.

Can you send us a pointer where we can find info on how to make this work ?