discount code importer is not working

### Support reference number

https://jira.commercetools.com/servicedesk/customer/portal/1/SUPPORT-9100

### Description
I am trying the following doc to import and export coupons from CT, and it is not connecting to CT.

for Importer module, tried the following :

sphere import -t discountCode -f ./R3G2F_Coupons.json --authProtocol https --authHost https://auth.att.us-east-1.aws.commercetools.com --protocol https --host https://api.att.us-east-1.aws.commercetools.com --accessToken 5mZcYvXQ2kq7NYlfr9Hb7DNncoKxuEFV

Code :
const discountCodeImport = new DiscountCodeImport(options);

discountCodeImport.run(codes)
.then(() => {
discountCodeImport.summaryReport();
// handle successful import
})
.catch((error) => {
// handle error
});

### Expected Behavior

It should be creating coupons by reading from the files generated by generator module.

### Current Behavior

It is not importing discount codes and not even showing any errors on why its failing.

### Context

We are trying to create a million discount codes using this feature, but its not working.

### Possible Solution

Please fix the importer module, so that it can import the generated discount codes with 500 concurrent streams.