Forum Discussion

Sunil Guntupalli's avatar
Sunil Guntupalli
Copper Contributor
May 08, 2018
Solved

Project Online/SharePoint Online "401 Unauthorized" error when accessing oData URLs programatically

Hi All, I couldn't authenticate Project Online oData URLs using the below piece of code in a C# console application. It was working fine till yesterday from past 1 year. SecureString passWord =...
SharePoint Online
  • Daniel Colarossi's avatar
    Daniel Colarossi
    May 09, 2018

    Hi All,

     

    Another work around is to generate a SharePoint client context and then grab the auth cookie from those credentials and pass it to the rest api request.

     

    authCookie = creds.GetAuthenticationCookie()

    req.Headers.Add(HttpRequestHeader.Cookie, authCookie);

     

    Let me know if you need more details

     

    Thanks

     

    Dan

Daniel Colarossi's avatar
Daniel Colarossi
Copper Contributor
May 09, 2018

Hi Sunil,

 

Something has recently changed and you're not alone in this issue.  It's been slowly rolling out to tenants this week :(   

 

The issue is isolated to the rest apis, so if you can switch your code over to use the CSOM libraries then it will authenticate correctly.

 

  ProjectContext pc = new ProjectContext(url)

 

We have escalated to Microsoft, if we hear of anything I'll update this post.  Please let us know if you hear anything.

 

Thanks

 

Dan

JOÃO LEITE BRAGANÇA's avatar
JOÃO LEITE BRAGANÇA
Copper Contributor
May 09, 2018

It is curious you mentioned that things are changing. From last weekend to today (9 May 2018) I am also getting the 'The Remote server returned an error: (401) Unauthorized' System.Net.WebException error, where the detail status tells "ProtocolError". The unmodified, proven-tested and working until today CSOM code I tried to run (repeat: always worked fine) with SharePoint Online was:

 

ClientContext context = new ClientContext(serverUrl);

SecureString securestringpassw = new SecureString();
foreach (char c in password) { securestringpassw.AppendChar(c); }

SharePointOnlineCredentials creds = new SharePointOnlineCredentials(username, securestringpassw);

context.Credentials = creds;
context.RequestTimeout = 60000; // ms

Web web = context.Web;

var list = web.Lists.GetByTitle(Library);
context.Load(list.Fields);
context.ExecuteQuery();  // Error 401 here

 

 

I really curious on what is going on... Any clues?

 

Many thanks!

 

Resources