Using PharoCloud: 500 Internal Server Error (nginx)

I am playing for the first time with PharoCloud. I do the following steps:

- download Pharo 6 image

- open the image and execute `ZnServer startDefaultOn: 8080`

- tests http://localhost:8080 (I see Zinc welcome message)

- save and quit the image and compress the image and changes

- login to PharoCloud using Pharo Association account https://www.pharocloud.com/manager/connect 

- upload the ZIP archive with Pharo image and changes using PharoCloud Ephemeric Manager v3.0 web interface

- set expose ports to 8080 and submit the configuration

- activate the image, it asks me to login again (and I login with Pharo Association account)

- the image is active (green circle)

- click on its hostname and I see 500 Internal Server Error (nginx) instead of the welcome message

Is it suppose to work? Do I miss something? 

Thanks,

Juraj