Microsoft Exchange: "Windows credentials need to be assigned"

JoachimT

I  added "Microsoft Exchange" to a node, added the monitoring user to "View-Only Organization Management" and enabled WinRM to be able tio talk to it over HTTPS. The node generally uses the agent. The user was local admin already before.
Also "New-ManagementRoleAssignment -Role "Mailbox Search" -User xxx"

I'm now stuck in the test of the "Microsoft Exchange" application in the SAM settings:

(PS: Because of a company policy I can't use the Auto Config for Exchange servers!)

The node itself tells me

Up Exchange 2016 Client Access Role Services and Counters (Basic) Up
Up Exchange 2016 Hub Transport Role Service and Counters (Basic) Up
Unknown Microsoft Exchange Unknown
Up Microsoft IIS Up

AppInsight for Exchange -> Microsoft Exchange: "Windows credentials need to be assigned."

Admin -> Settings -> SAM Settings -> Edit Application Microsoft Exchange

Exchange Server Credentials: inherit from node

Test Connection:

"WinRM test was successful.
PowerShell Exchange web site testing failed with the following error:
Object reference not set to an instance of an object."

The Local Exchange Endpoint seems to be correct. What is missing?

JoachimT

I also added the monitoring user with "Set-PSSessionConfiguration Microsoft.PowerShell -ShowSecurityDescriptorUI -Force" with full access (https://www.solarwinds.com/documentation/en/flarehelp/sam/content/sam-setting-powershell-permissions-sw1456.htm) and run the scriupt here https://support.solarwinds.com/SuccessCenter/s/article/Update-PSLanguageMode-PowerShell-settings-for-target-AppInsight-for-Exchange-nodes-in-SAM?language=en_US

No change

"WinRM test was successful.
PowerShell Exchange web site testing failed with the following error:
Object reference not set to an instance of an object."