I'm having a bit of trouble using the SharePoint 2010 REST services on one of our servers. We have two production servers, and if I point my system to one of the servers I am able to connect to the REST service API with no trouble. However, if I point it to the other server I get a 401 unauthorised error.

It's the same SharePoint service on both servers, our environment uses a load balancer to divide traffic between them, and both share the same database.

Can anyone think why this might be happening? I could understand if it just wasn't working at all, but I'm puzzled as to why it works perfectly on one box but not the other.

Thanks for any help!

  • Using browser are you able to open up the site by direct url to the second server? Oct 21 '14 at 15:45
  • Thanks for replying! Yes. I can browse to my SharePoint site by direct URL on both servers with no trouble. However, when I use the REST URL on one box I get the result I expect, but on the other I get an error message stating that it could not load type: system.data.services.providers.idataserviceupdateprovider
    – Mark
    Oct 21 '14 at 15:50
  • 1
    Actually, that may have answered my question. On googling that error, it looks like there may be an update from Microsoft that needs installed.
    – Mark
    Oct 21 '14 at 15:52

Make sure both servers has latest ADO.Net Data Services installed




Looks like you are missing a HotFix for .net 3/5 SP1 on one server, which is also part of pre requisite of SharePoint 2010(ADO.NET Data Services Update for .NET Framework 3.5 SP1).

Now install the required hotfix as per your Windows Server OS.

for Windows Server 2008 SP2

for Windows Server 2008 R2 or Windows 7

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