Application.RegisterXLL fails with COM Exception 0x800AC472

Question

Hi,

We have a .NET application which uses Excel DNA for calculations and HMI. This application tries to register couple of Excel AddIns when the program starts. It works fine with Win10 - Excel 2016 combination. We have a requirement to support Windows 2019 server - Excel 2016 now. While validating our product on 2019 server, the registration of XLL fails with the following COM exception.

System.Runtime.InteropServices.COMException (0x800AC472): Exception from HRESULT: 0x800AC472
at Microsoft.Office.Interop.Excel.ApplicationClass.RegisterXLL(String Filename)
at EmbeddedExcel.ExcelApplicationExtensions.InvokeRegisterXll(Application excelApplication, String fileName)

I tried to register these XLLs using a simple .NET console application on the same PC and it registers the XLL successfully. I could not understand

1. What has changed from Windows 10 to Windows 2019 that could break these Xlls from registering. Please note that it's same Excel version, 2016( version 16.0.4266.1001) 32 bit, on both these machines.
2. Why it succeeds with the sample program and fails with our .NET application.

I appreciate any help in resolving this issue ASAP.