windows – Outlook and RSS feeds from SharePoint 2016

We are currently experiencing a strange behavior with Perspective when some users want to subscribe to a RSS food.

We have an intranet infrastructure that is a SharePoint 2016 on-site installation that uses ADFS as an authentication provider but also NTLM for some services.

For some reason we can not understand, some users can not subscribe to RSS the foods that come from our SharePoint installation by Perspective. Perspective always returns that the content of the RSS the feed can not be processed or the link used may not point to a valid source.

All users experiencing this problem are fully authenticated on their computer and can reach the SharePoint infrastructure without any problem. They can also display the different RSS stream in their browser or subscribe via their browser. They are all referenced in SharePoint with at least read permission and synchronized in the Central administration. The problem occurs on the lists or libraries to which they have access.

the RSS foods from SharePoint are valid. At first we used a Web (CQWP from Imtech) which displays on a page elements and a link to subscribe to a corresponding message. RSS food. We thought this component was the problem, so we changed it for the standard CQWPbut the problem was the same. We also noticed that the problem occurs when users use the generated link for the RSS Available stream in the ribbon of a list or library, but only once. The first time they use the link, it fails, but if they try again, it works and they can delete and add the feed as many times as they wish.

We followed the different HTTP requests that are sent when the problem occurs and in some cases we have noticed a 401 error, as if users could not be authenticated when they make a request to our SharePoint installation from Perspective. We tried to add user accounts in two formats in our SharePoint installation (ADFS and ONE D), but the error persists even when users have full control.

We have tried various solutions of Microsoft, including the workaround where we have to synchronize the RSS feeds Common flow list (https://support.microsoft.com/en-us/help/917125/error-message-when-you-subscribe-to-an-rss-feed-that-requires-authenti) or the trick with the registry key "HKCU Software Microsoft Office 16.0 Outlook Options RSS Disable"Without success, we even thought it was linked to some of the characters in the generated URLs and we played them many times, whether they use coded characters or not.

We are a big organization with a lot of complex rules, but we checked with the server team, the network team and the security team, and there is no rule or parameter on that side that can block the connection between Perspective and SharePoint.

Most users use Windows 10 and Office 2016but the problem also arises with Windows 7 and Office 2010. Whereas our SharePoint The infrastructure is operational and does not seem to be a security or network problem, it seems linked to the Office the installation or perhaps the profile of the user, but we can not find more documentation on this problem.

We tried many things for hours to understand why it was not working, but without success. Has anyone encountered such behavior? Any suggestion would be greatly appreciated.

Best regards,