JSON parse error: Unexpected character ('n' (code 110)): was expecting comma to separate Object entries

The URL does not have any special characters,

/api/ws-server/message

It is a POST, it does have escaped characters, and the body looks like below. (it is a constructed message in multiple layers, hence the various escapes)

{
“topic”: “/topic/service/device/message”,
“message”: “{ "devices": [{ "deviceIndicator": "pts", "deviceDuiIndicator": "pts-gui", "deviceProperties":{ "DASSystemConfig": "{ \"name\": \"CPTS TestSystem\" }" }, "status": { "deviceIndicator": "pts", "status": "READY", "statusProperties":{ "DASSystemState": " { \"errorSignal\" : \"OK\", \"doNotLoad\": \"true\" }" }, "level": "READY" } } ], "timestamp": "2019-12-03T14:02:07.971Z", "messageId": "e9265edb-c3e8-42e0-96c9-a826b418cd41", "messageClass": "DALDeviceInfoV1" }”
}

Sending this exact message through to the endpoint using the Object Repository results in a 200.
But calling the endpoint from the test using WS returns the 400

WS.sendRequest(findTestObject(‘websocket mock/send message’, [(‘url’) : GlobalVariable.WS_MOCK_URL, (‘message’) : msg]))

I don’t have a .har file