Braintree and Node.js Creating Sub Merchant Error Not Authorized

I am using the node.js braintree sdk to try creating sub merchant accounts. However, it has been unsuccessful so far and I keep getting a not authorized error but I don't know how to pass the token in this call.

Here's the gateway I am using:

// gateway
const braintree = require("braintree");

const gateway = new braintree.BraintreeGateway({
    environment: braintree.Environment.Sandbox,
    merchantId: process.env.BRAINTREE_MERCHANT_ID,
    publicKey: process.env.BRAINTREE_PUBLIC_KEY,
    privateKey: process.env.BRAINTREE_PRIVATE_KEY
});

And here's the call I'm making:

// sub merchant call


exports.createSubMerchant = async (req, res) => {
    let {
        firstName,
        lastName,
        email,
        phone,
        dateOfBirth,
        ssn,
        address1,
        address2,
        locality,
        region,
        postalCode,
        businessLegalName,
        businessDbaName,
        taxId,
        businessAddress1,
        businessAddress2,
        businessLocality,
        businessRegion,
        businessPostalCode,
        fundingDescriptor,
        fundingDestination,
        fundingEmail,
        fundingMobilePhone,
        fundingAccountNumber,
        fundingRoutingNumber,
        tosAccepted,
        id
    } = req.body;

    const merchantAccountParams = {
        individual: {
          firstName: firstName,
          lastName: lastName,
          email: email,
          phone: phone,
          dateOfBirth: dateOfBirth,
          ssn: ssn,
          address: {
            streetAddress: `${address1}${address2 ? `, ${address2}` : null}`,
            locality: locality,
            region: region,
            postalCode: postalCode
          }
        },
        business: {
          legalName: businessLegalName,
          dbaName: businessDbaName,
          taxId: taxId,
          address: {
            streetAddress: `${businessAddress1}${businessAddress2 ? `, ${businessAddress2}` : null}`,
            locality: businessLocality,
            region: businessRegion,
            postalCode: businessPostalCode
          }
        },
        funding: {
          descriptor: fundingDescriptor,
          destination: fundingDestination, // braintree.MerchantAccount.FundingDestination.Bank,
          email: fundingEmail,
          mobilePhone: fundingMobilePhone,
          accountNumber: fundingAccountNumber,
          routingNumber: fundingRoutingNumber
        },
        tosAccepted: tosAccepted,
        masterMerchantAccountId: process.env.BRAINTREE_MERCHANT_ID,
        id: id
      };
      
        try {
            let result = await gateway.merchantAccount.create(merchantAccountParams)
            console.log(`result: `, result)
            res.json(result)
            
        } catch (e) { console.log(e); res.json({error: e}) }

    
};

The result is this error:

UnauthorizedError: No authorization token was found

But I don't see where to add the token when looking at the Merchant Account: Create docs of braintree.

Please share if you have the solution on how to make this call to add sub merchants.

After receiving a response from Braintree, they confirmed they no longer offer this program.