Error: "The module cannot be loaded because only single file assemblies are supported" in .NET Core

Despite having a several years background in .NET backend, I'm a newbie in cross-platforms, hence in .NET Core. I'm struggling the below error during runtime of the component developed in .NET Core 3.1 framework which is a worker service (introduced in .NET Core 3.x).

Any ideas folks?

Important: This .netmodule file is already being utilized in our current backend in .NET environment bundled with another .dll assembly file(s). I know that most of the .NET 3rd party libraries are NOT compatible with .NET Core area. However, I'm not sure whether there's a hidden catch on the issue; since when I google'd the error message, I could not find any exact match.

System.IO.FileLoadException: Could not load file or assembly 'dcpssacs.netmodule'. The module cannot be loaded because only single file assemblies are supported. (0x8013101E)
File name: 'dcpssacs.netmodule'
   at DDSMessageReceiver.Core.GenericSimplicityLayer.DefaultSettings(BaseModel& baseModel)
   at DDSMessageReceiver.Worker.InitializeModules() in C:\Triodor_Workspace\T4CNext\DDSMessageReceiver\DDSMessageReceiver\Worker.cs:line 83
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__139_1(Object state)
   at System.Threading.QueueUserWorkItemCallbackDefaultContext.Execute()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()