PBI Rest API - Create datasource in gateway error

Hi, everyone

I hope someone can help me. I'm trying to create a datasource in a gateway using PBI Rest API and it shows an error. The body I'm using is the one that is in documentation.

Body

{
  "dataSourceType": "SQL",
  "connectionDetails": "{\"server\":\"MyServer\",\"database\":\"MyDatabase\"}",
  "datasourceName": "Sample Datasource",
  "credentialDetails": {
    "credentialType": "Windows",
    "credentials": "AB....EF==",
    "encryptedConnection": "Encrypted",
    "encryptionAlgorithm": "RSA-OAEP",
    "privacyLevel": "None"
  }
}

Response

{
  "error": {
    "code": "DM_GWPipeline_UnknownError",
    "pbi.error": {
      "code": "DM_GWPipeline_UnknownError",
      "parameters": {},
      "details": [
        {
          "code": "DM_ErrorDetailNameCode_UnderlyingErrorMessage",
          "detail": {
            "type": 1,
            "value": "Invalid Ciphertext size. Expecting cipher text of atleast length, 344. Provided cipherText length, 10"
          }
        },
        {
          "code": "DM_ErrorDetailNameCode_UnderlyingHResult",
          "detail": {
            "type": 1,
            "value": "-2146233296"
          }
        }
      ],
      "exceptionCulprit": 1
    }
  }
}

Any tip?... 

Thanks in advance,