question

I'm trying to connect to a Flex 3 terminal running on Emulator in Android Studio, connected to the sandbox account (cuongtm2@smartosc.com).

I can download information about the list of devices but I cannot send e.g. a message to the device using the API: "https://sandbox.dev.clover.com/connect/v1/print/text". I use tokens from Account & Setup/API Tokens with full permissions

{
  "text": [
    "Hello World"
  ]
}

I get error 500 as below.

I haven't found any information on what it means. How should I interpret this message? How to solve the problem?

{
  "message": "Could not verify authentication token with COS server.",
  "requestId": "8acae36f-33566",
  "requestType": "PRINT_TEXT_ON_DEVICE",
  "type": "ERROR"
}