I've this snippet code. In some point of this code, I can obtain response.send... in other points, I obtain the error response.send is not a function. Below I highlight in which points this happens:

router.post("/*", function (request, response) {

  if (request.path === "/permissions") {
  ...

    if (!error_json) {

      (async () => {

        var cookie = request.cookies['JSESSIONID'];
        var user_cookie = "JSESSIONID=" + cookie;
        var devices = [];
        var number;
          const response = await axios.get("http://10.10.0.145/api/devices", {
            headers: {
              'Cookie': user_cookie
            }
          })
          for (let i = 0; i < response.data.length; i++) {
            devices[i] = response.data[i].id;
          }
          if (!devices.includes(request.body.deviceId)) {
            return response.send("Device ID does not exist."); //DOESN'T WORK
          } else {

            try {

              const intervention_found = await tc_interventions.find_intervention(request.body.interventionId);
              if (intervention_found < 1) {
                return response.send("Intervention ID does not exist."); //DOESN'T WORK
              } else {
                number = await tc_device_intervention.find_device_intervention(request.body.deviceId, request.body.interventionId);
                if(number < 1){
                await tc_device_intervention.insert_device_intervention(request.body.deviceId, request.body.interventionId);
                }
              }


            } catch (err) {
              console.error(err);
            }

          }

        if(number < 1){
        return response.status(201).send(request.body); // WORKS
        }else{
          return response.send("Device-Intervention existing yet."); //WORKS
        }
      })();

      return;

    }

  }

});