SCCMProviderGraph.exe crashing

Out of the blue yesterday the application log on our (lone) site server started showing:

Faulting application name: SCCMProviderGraph.exe, version: 5.0.9128.1007, time stamp: 0xe9a8eeaa

Faulting module name: KERNELBASE.dll, version: 10.0.20348.2694, time stamp: 0x0b989c63

Exception code: 0xe0434352

Fault offset: 0x000000000003f14c

Faulting process id: 0x92c

Faulting application start time: 0x01db1b3bd5facf85

Faulting application path: D:\Program Files\Microsoft Configuration Manager\bin\x64\CMRestProvider\SCCMProviderGraph.exe

Faulting module path: C:\Windows\System32\KERNELBASE.dll

Report Id: 31f979af-9412-4431-b172-23e03407309d

Faulting package full name:

Faulting package-relative application ID:

A reboot of the server did not solve the problem.

13 seconds before the errors started, the MSI installer service showed:

"Windows Installer reconfigured the product. Product Name: ConfigMgr Management Point. Product Version: 5.00.9128.1000. Product Language: 1033. Manufacturer: Microsoft Corporation. Reconfiguration success or error status: 0."

The adminservice.log shows constant errors:

Message: Could not load file or assembly 'Microsoft.ConfigurationManager.ObjectLibrary, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)

Inner Exception:

Message: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework. This release of the .NET Framework does not enable CAS policy by default, so this load may be dangerous. If this load is not intended to sandbox the assembly, please enable the loadFromRemoteSources switch. See http://go.microsoft.com/fwlink/?LinkId=155569 for more information.

To me this means a .NET .config file needs to have the loadFromRemoteSources switch added but I don't know which file needs to be edited.

Can anyone help?

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