Request with query params fails - http

Question

I have the following code to make an http request to a third party service:
... // more code
payl, err := json.Marshal(payload)
if err != nil {
result <- models.HHResult{
Result: "",
StatusCode: 0,
Error: err,
}
return
}
req, err := http.NewRequest(method, url, bytes.NewReader(payl))
q := req.URL.Query()
for k,v := range params {
q.Add(k,v)
}
req.URL.RawQuery = q.Encode()
client := http.Client{
Timeout: time.Millisecond * time.Duration(timeout),
}
resp, err := client.Do(req)
if err != nil {
result <- models.HHResult{
Result: "",
StatusCode: 0,
Error: err,
}
return
}
respbytes, err := ioutil.ReadAll(resp.Body)
defer resp.Body.Close()
result <- models.HHResult{
Result: string(respbytes),
StatusCode: resp.StatusCode,
Error: nil,
}
... // more code
The same works fine when not using query parameters. But when I do use params as :
tokenResponse = <-(apic.httpHelper.RequestWithOptions("GET", url,nil, map[string]string{
"user" : viper.GetString("userid"),
"password" : viper.GetString("pwd"),
The service is telling me I am missing required parameters.
If I print the request previously to actually doing it using curl/postman then it works fine.
What might I be doing wrong?
Third party service example:
https://auth.service.com/v1/oauth/token?user=matias&password=1234