How to do basic auth to acces external url and advoid System.HttpResponse[Status=Forbidden, StatusCode=403]

Question

I have a basic auth which I have working with Postman but when I do this with apex I get an Forbidden error. The variables userKeyVal and userSecretVal are filled correctly, my url is correct and I granted acces trough remote site setings. What am I missing.

Postman

    **Key**             **Value**      
    Content-Type    application/json
    Authorization   Basic AAAAAAAAAAAAAAAAAAAAAAAAAAA==

Update(not needed):
    client_id       123456789  
    client_secret   BBBBBBBBBBBBBBBBBBBB

Apex

  @TestVisible static Boolean doCallout = true;
    @future(callout=true)
    //Get Stock
    public static void  getStock() {
        if(doCallout) {
        fetchConfiguration();   
            Http http = new Http();
            HttpRequest request = new HttpRequest();
            request.setEndpoint(UrlVal +'stock/?');
            request.setMethod('GET');
            request.setHeader('Content-Type','application/json'); 

            Blob headerValue = Blob.valueOf(userKeyVal + ':' + userSecretVal);
            String authorizationHeader = 'BASIC ' +EncodingUtil.base64Encode(headerValue);
            request.setHeader('Authorization', authorizationHeader);

            HttpResponse response = http.send(request);
            if (response.getStatusCode() == 200) {
            System.debug('response: ' + response);
            }
        }
    }

Answer 1

For someone how bumps into this. Im my case the code was working properly. The Ip addresses of Salesforce needed to be whitelisted on the other end.