At the moment the apps from Ecwid App Market don't open in Control Panels.
You might see the following error while opening an app: Oops! We were unable to prepare installation due to an internal problem. Please contact us at firstname.lastname@example.org
We're on this issue. All your data (products, orders, customer details, store settings, etc) is safe and intact.
Please accept our sincere apologies for this problem. We'll be posting updates here.