Error 400 with GET request

Hi all, I’m new to Bravo and want to try to connect the rest api of Lightspeed ECOM shop to an app. I uploaded the postman collection from Lightspeed and tried out to get all the customers form the rest api.

The get https://${api_key}:${api_secret}@api.${cluster}.com/nl/customers.json gives a 400 error. Of course I filled the api_key, api_secret and the cluster variable. This one is working in Postman but not in Bravo.

The problem is that "${api_key}:${api_secret}" is not send by Bravo. I looked at the debug screen where I can see what URL is send to rest api and it is only – 

Request URL:https://api.webshopapp.com/nl/customers.json

I’m missing before the “@” sign the api_key and api_secret.

I also tried to put the api_key and api_secret directly in the GET HTTPS request. But still I got an error 400 return with in the debug screen the same URL send to the lightspeed rest api as above.

I’m doing something wrong but I do not know what.