Unable to add a survey translation

Hi,
I'm using the following API call to create a survey translation but it's failing with 400 - Bad Request:
CURL Request:
curl --location --request PUT 'https://iad1.qualtrics.com/API/v3/surveys/{MY_SURVEY_ID}/translations/ES' \\
--header 'x-api-token: {MY_API_TOKEN}' \\
--header 'Content-Type: application/json' \\
--data-raw '{
  "QID1311637079_QuestionText": "Translated Text"
}'
Response:
{
"meta": {
"httpStatus": "400 - Bad Request",
"error": {
"errorCode": "QMST_1",
"errorMessage": "The request was invalid."
}
}
}
Am I missing anything?
I also tried adding the language (ES) with the following API call before I add a survey translation but that didn't help either.
https://ca1.qualtrics.com/API/v3/surveys/{surveyId}/languages
Please help!!