Cannot Create ViM at portal.azure.com

I  tried to create Ubuntu 14.04 vm on japan west at portal.azure.com.

However, suddenly it stops deploying vm with a following error. 

BadRequest {"error":{"code":"InvalidParameter","target":"windowsConfiguration","message":"The value of parameter windowsConfiguration is invalid."}}

I also retried to create a vm many times, and always got above errors.

How can I bypass that problem and create a vm?