Hybrid sites problem in SharePoint 2013

[Thomas Vochten]

One of my customers ran the hybrid configuration wizard with success, but their users are unable to use the hybrid sites functionality: whenever they follow a site, they get a 401 error in the logs:

FollowedContent.FollowItem:Exception:System.Net.WebException: The remote server returned an error: (401) Unauthorized.

All users have SharePoint Online licenses assigned to them in Office 365 and identity synchronization has been configured. In the on-premises farm the trust has been configured as the ACS service application proxy, the SPTrustedSecurityIssuer and the matching root authority certificates are all in place.

They also activated hybrid OneDrive and Profiles, and that seems to work - although that's just a redirect of course and not a CSOM call...

They are using SharePoint Server 2013 with the October 2017 cumulative update.

Any ideas?

[#2]

I had some similar problems quite early on with SharePoint search in Hybrid mode where search requests weren't being passed to SPO correctly. In the end with help from the MS Hybrid gurus, we traced the problem down to the servers not accessing the proxy correctly for outbound connections.

We had to run "Netsh winhttp set proxy "proxydnsname:8080" on each query server to ensure that the server could talk out to the internet and access the web services for SPO. We didn't need authentication as it was just a dumb proxy. For some reason it was ignoring whatever was set in IE on the server and only played correctly when Netsh was used.

[#3]

I'll let them test that out asap. Thanks for the feedback, Paul!