Failure to Create Users in Sandbox Environment

[vizawa]

Hi,

After some weeks that I created my sandbox's account, when I try to create user, I got this error: 

{
  "error_message" : "Service Unavailable",
  "error_code" : "503000"
}

I tried some times but not successful and I didn't know if there's a problem into my sandbox's account. Is there a support channel for sandbox's users?

Thanks and good week!