We are trying to host our application in the Calponia service portal. After successfully pushing the code and starting the Sandbox we are not able to stop it manually. The sandbox gets automatically stopped after one day then only we are able to integrate our further code changes. Currently we are using a free plan of Calponia portal.
Only project owners can start and stop instances in their projects. So you either ask one of your project owners to stop it or you go for the belonging owner role in that or a new project.
Our UI should be more clear on that error. I will transfer the feedback. Thank you.