How to fix Invalid JSON payload error from the Google Ads API

I'm trying to pull a report from the Google Ads API into Google sheets and I can't get the API to recognize my query as a query

Here's the code and error I'm getting:

    function basicReport() {   var query = {     "query" : "SELECT campaign.name, campaign.status FROM campaign ORDER BY campaign.id"   };      var body = JSON.stringify(query);      var head = {     'Developer-token' : "<Dev token>",     'login-customer-id' : <Manager ID>,     'Authorization' : "Bearer <Auth token>",   }; var options = {   'method' : 'POST',   'content-type': 'application/json',   'headers' : head,   'payload' : body,   'muteHttpExceptions' : true };    var response = UrlFetchApp.fetch('https://googleads.googleapis.com/v4/customers/<Customer ID>/googleAds:searchStream', options);   var json = response.getContentText();   var data = JSON.parse(json); 

But I constantly get the error:

"error": {     "code": 400,     "message": "Invalid JSON payload received. Unknown name \"{\"query\":\"SELECT campaign.name, campaign.status FROM campaign ORDER BY campaign.id\"}\": Cannot bind query parameter. Field '{\"query\":\"SELECT campaign' could not be found in request message.",     "status": "INVALID_ARGUMENT",     "details": [       {         "@type": "type.googleapis.com/google.rpc.BadRequest",         "fieldViolations": [           {             "description": "Invalid JSON payload received. Unknown name \"{\"query\":\"SELECT campaign.name, campaign.status FROM campaign ORDER BY campaign.id\"}\": Cannot bind query parameter. Field '{\"query\":\"SELECT campaign' could not be found in request message." 

I've run the query in OAuth playground (https://developers.google.com/oauthplayground) and it worked there, so I know the query is ok.

I've tried passing the body as an object not a string, but then I get a 500 error.