StartRoleOperation - how to get info about internal server error?

I'm attempting to start a Virtual Machine by a HTTP POST request:

https://management.core.windows.net/{subscriptionId}/services/hostedservices/{svcName}/deployments/{dplyName}/roleinstances/{roleName}/Operations

ContentType = "application/xml"

PostData:

<StartRoleOperation xmlns="http://schemas.microsoft.com/windowsazure" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<OperationType>StartRoleOperation</OperationType></StartRoleOperation>

Of course I'm passing the x-ms-version header with "2013-06-01" value.

I got HTTP 202 (Accepted) answer

but then nothing happens. The same code worked last week, but now it doesn't. I surely made no changes.

The Service Dashboard (http://azure.microsoft.com/en-us/status/) says that everything is OK, especially VM-related services in all regions. My VM is in the East US region.

What am I doing wrong? What more should my program do to notice that the VM haven't started and retry? How long should I retry?
(currently it does not work for 2+ hours!)

Any help is appreciated.

EDIT: Is there another API method to start a VM from deallocated state? Because retrying this one is clearly useless.

EDIT: Even the Management Portal cannot start the server. It tells "Failed to start virtual machine {name}"  Details: "The server encountered an internal error. Please retry the request."

Now my question is: how to get the same info programmatically?