Cannot create VM instance of self-made Image: HTTP 500

I made a VM with Win2012 from the Gallery, added some custom components and ran sysprep. Captured the VM so that it became available in the Image tab.

Now, when I use Powershell to create a new VM based on this image, it returns: "An exception occurred when calling the ServiceManagement API. HTTP Status Code: 500. Service Management
Error Code: InternalError. Message: The server encountered an internal error. Please retry the request.. Operation
 Tracking ID: a3cfa5e9-8b6f-4f90-aae7-1d9f415500d7."

The same via the Management Portal: The server encountered an internal error. Please retry the request. The long running operation tracking ID was: 58114a300241408f94ccff7b2a5f5434.

Any help is appreciated.