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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!

     

  • Joe Fedorowicz's avatar
    Joe Fedorowicz
    Iron Contributor
    May 09, 2018

    I'm seeing something similar with a REST call in a workflow that creates a subsite. Get a "Forbidden."

     

    So it has worked forever, and works on some sites...but not on new ones. 

    • Daniel Colarossi's avatar
      Daniel Colarossi
      Copper Contributor
      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

      • JOÃO LEITE BRAGANÇA's avatar
        JOÃO LEITE BRAGANÇA
        Copper Contributor
        May 09, 2018
        But yes, Daniel, your suggestion does work!

        Still I am curious on what is going on!

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