Can't get results from backend returned to front end

I am having trouble returning an object to front end from a function on my backend. (The password function in the code is just for testing purposes).

What I am doing is receiving some data on another platform (stripe) then getting it over to wix and registering the customer. Then, I want to return the “registrationResult” object to the front end so I can then log the user in with code and redirect him/her to a specific member’s page with path /myplan.

The PROBLEM I am having is that the “registrationResult” on the front end side comes out as UNDEFINED.

I do not understand because whenever I run the code from the backend console (image attached) I do get a return value but whenever I try it live it comes out as undefined.

Code in BACKEND:

export async function updateGuarCustomersInDB(checkoutSession) {
  var returnValue
  const session = await key.checkout.sessions.retrieve(checkoutSession);
  const customer = await key.customers.retrieve(session.customer);
  function generatePassword() {
    var length = 8,
        charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
        retVal = "";
    for (var i = 0, n = charset.length; i < length; ++i) {
        retVal += charset.charAt(Math.floor(Math.random() * n));
    return retVal;
  let password = generatePassword();

  await authentication.register(, password, {
          "contactInfo": {
            "firstName": first,
            "lastName": last
    .then((registrationResult) => {
      returnValue = registrationResult;
      assignRole("ACTIVE", registrationResult.member._id)
     .then(() => {
      .catch((err) => {
    .catch((error) => {

    return returnValue;


    if(wixLocation.query.checkoutSession != null){
        .then((registrationResult) => {
            .then(() => {
    } else {

Image of code being ran on the backend console:

You can see the object that is being returned whenever I run the function. But if I try it live the image below happens.

Image of the error i get when i try that code live:

I have been struggling with this. I do not know how to fix it. Please help me find a solution or a work around.

I also tried to log the user in on the backend but for some reason it would not let me access the /myplan page. It redirected me to the default login page wix offers but since I have a custom login then that would not work.