Storing variables

I’m new to Kantu and having problems storing and using variables as below:

  1. I create a Variable
    {
    “Command”: “store”,
    “Target”: “UI422815”,
    “Value”: “UserName”
    },

  2. I then go onto use that variable as an input value in the next step:
    {
    “Command”: “type”,
    “Target”: “id=loginform:username”,
    “Value”: “${USERNAME}”
    },

However I then get the following error, and notice the variable disappears from my variables list:

[error] variable “USERNAME” is not defined

Any ideas?

I made a short test macro and it works for me:

{
  "CreationDate": "2018-11-8",
  "Commands": [
    {
      "Command": "store",
      "Target": "UI422815",
      "Value": "UserName"
    },
    {
      "Command": "open",
      "Target": "https://a9t9.com/contact",
      "Value": ""
    },
    {
      "Command": "type",
      "Target": "id=Email",
      "Value": "${USERNAME}"
    }
  ]
}