I am getting this error from salesforce as the response. "{"Fault":{"Code":{"Value":"s:Receiver","Subcode":{"Value":"a:Security_MissingAuthorization"}},"Reason":{"Text":{"lang":"en-US","Value":"Missing the mandatory 'http://www.reuters.com/ns/2006/05/01/webservices/rkd/Common_1:Authorization' SOAP header in the user request."}},"Detail":{"ClientErrorReference":{"Timestamp":"2017-10-13T18:33:06.31979Z","ErrorReference":"df3ba8bccdaa40f584bef8aae519f08d","ServerReference":"D0B4498C3E7872E69F382B5CE83AEDFCFC5D463AB8375163"}}}}" // Below is the code String username = 'removed'; String password = 'removed'; string appId = 'removed'; // Instantiate a new HTTP request, specify the method (GET) as well as the endpoint HttpRequest req = new HttpRequest(); req.setMethod('POST'); req.setEndpoint('https://api.trkd.thomsonreuters.com/api/BrokerEntitlementsManagement/BrokerEntitlementsManagement.svc/REST/BrokerEntitlementsManagement_1/GetBrokerUsersEntitlements_1'); Blob headerValue = Blob.valueOf(username +':'+ appId +':'+ password); system.debug('authorizationHeader '+ authorizationHeader); req.setHeader('Authorization', authorizationHeader); req.setHeader('Content-Type', 'application/json'); req.setHeader('Accept', 'application/json'); stirng jsonBody = '{"GetBrokerUsersEntitlements_Request_1":{"getUserLogin":true,"ctbId":sampleID-Number,"sortByCompany":{"field1":"Id","field2":"Id","field3":"Id","order":"Asc"},"sortByUser":{"field1":"FirstName","field2":"FirstName","field3":"FirstName","order":"Asc"},"search":{"byUserEmail":{"email":[{"type":"some sample data"}]}}}}'; req.setBody(jsonBody); // Send the request, and return a response HttpResponse res = new http().send(req); system.debug('PSM ' + res.getBody());