UPDATE: The following update is fixing this issue:
- Cumulative Update for Windows 10 Version 1607 and Windows Server 2016: December 9, 2016 https://support.microsoft.com/en-us/kb/3201845
If you are currently using the October release of Windows Server 2016 (build: 10.0.14393 N/A Build 14393) you might experience a weird error message when you try to add a relying party trust or update a relying party trust with the metadata files. Whether it is from an HTTPs source or even a local XML files that you previously saved, you have the following message:
It seems that adding or updating a relying party from the console currently does not work as expected. If you don't know what version of Windows you are running, you can run the command "systeminfo" in command prompt and look at the build line.
But no worry, you can still do the job thanks to our good old friend PowerShell.
Adding a relying party trust from an online metadata file:
Add-AdfsRelyingPartyTrust -Name "My App" -MetadataUrl "https://web.piaudonn.com/app/federationmetadata/2007-06/federationmetadata.xml"
Adding a relying party trust from a metadata saved on the your ADFS server:
Add-AdfsRelyingPartyTrust -Name "My App" -MetadataFile "C:\Temp\FederationMetadata.xml"
Updating the relying party trust from the metadata file already set on the properties of the trust:
Update-AdfsRelyingPartyTrust -TargetName "My App"
This will probably be fixed very soon!