Help a beginner - Go X-API-KEY error

Hi there - new to programming, but love Destiny, so thought as an intellectual exercise to learn Go, using Bungie APIs as a real world example. However, i'm falling early - can someone pls look at my code, and tell me why I keep getting "Please add valid X-API-Key header to request" errors? I'm sure it's something stupid on my part :) package main import ( "net/http" "net/http/httputil" "io/ioutil" "fmt" "log" ) func main() { var body []byte var response *http.Response var request *http.Request ApiToken := "PutYourAPIKeyHere" user := "PutYourUsernameHere" url := "https://www.bungie.net/Platform/Destiny/2/Stats/GetMembershipIdByDisplayName/" + user request, err := http.NewRequest("GET", url, nil) //if err == nil { request.Header.Add("Content-Type", "application/json") request.Header.Add("X-API-KEY", ApiToken) debug(httputil.DumpRequestOut(request, true)) response, err = (&http.Client{}).Do(request) //} if err == nil { defer response.Body.Close() debug(httputil.DumpResponse(response, true)) body, err = ioutil.ReadAll(response.Body) } if err == nil { fmt.Printf("%s", body) } else { log.Fatalf("ERROR: %s", err) } } func debug(data []byte, err error) { if err == nil { fmt.Printf("%s\n\n", data) } else { log.Fatalf("%s\n\n", err) } }