Webrequest returns 401 but same request using postman works

Question

I have a c# client that is calling a webapi web service (iis 6). I am able to execute my web calls successfully from postman - No Authentication (Normal tab). The same call from the c# webclient fails.

Looking at the requests in fiddler I don't see a difference between the two.

Below is the request I am sending (postman and webclient) no headers are set.

https://store.isswerver.com/api/details/Users - Succeeds from postman client

Returns 401 using c# client

_client = new WebClient();
_client.Headers.Add("Content-Type", "application/json; charset=utf-8");
_client.Headers.Add("Accept", "application/json");
 byte[] data = _client.DownloadData(string.Format("{0}/Users", _apiUrl));

The client does work if I run the website on my local machine.

What is different in the way postman is submitting the request?

HTTP 401 means Unauthorized so I would assume you are logged in when you do the request through the browser ? — pln
– pln, Commented Oct 2, 2014 at 14:08
What happens if you set _client.UseDefaultCredentials = true ? — pln
– pln, Commented Oct 2, 2014 at 14:30
_client.UseDefaultCredentials = true fixed it, I swear I had tried that Thanks! — user1127081
– user1127081, Commented Oct 2, 2014 at 15:02

Albireo · Accepted Answer · 2014-10-02 14:14:06Z

1

Check with a sniffer what Postman is actually sending on the wire and compare it with what you're sending for any kind of difference, both in the headers and the payload.

401 Unauthorized usually means you haven't supplied authentication credentials, however servers can return whichever status code they want for whichever reason (e.g. there's nothing preventing them to return a 401 status if they don't like the user agent).

answered Oct 2, 2014 at 14:14

Albireo

11.1k14 gold badges66 silver badges96 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Webrequest returns 401 but same request using postman works

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related