Cannot create unknown type - Package related

Hi All! i have deployed a project (includes mail processing, OCR etc) in a QA server and everything works fine. i uploaded the same package to Prod Orchestrator and while running the process, the Robot gives the following error:

An error appeared while executing DACH_Return_Request_Processing_Prod
Error message: Cannot create unknown type '{http://schemas.microsoft.com/netfx/2009/xaml/activities}OutArgument({http://schemas.uipath.com/workflow/activities}BusinessRuleException)’.
RemoteException wrapping System.Xaml.XamlObjectWriterException: Cannot create unknown type '{http://schemas.microsoft.com/netfx/2009/xaml/activities}OutArgument({http://schemas.uipath.com/workflow/activities}BusinessRuleException)’.
at System.Xaml.XamlObjectWriter.WriteStartObject(XamlType xamlType)
at System.Xaml.XamlWriter.WriteNode(XamlReader reader)
at System.Xaml.XamlServices.Transform(XamlReader xamlReader, XamlWriter xamlWriter, Boolean closeWriter)
at System.Activities.XamlIntegration.FuncFactory1.Evaluate() at System.Activities.DynamicActivity.OnInternalCacheMetadata(Boolean createEmptyBindings) at System.Activities.Activity.InternalCacheMetadata(Boolean createEmptyBindings, IList1& validationErrors)
at System.Activities.ActivityUtilities.ProcessActivity(ChildActivity childActivity, ChildActivity& nextActivity, Stack1& activitiesRemaining, ActivityCallStack parentChain, IList1& validationErrors, ProcessActivityTreeOptions options, ProcessActivityCallback callback)
at System.Activities.ActivityUtilities.ProcessActivityTreeCore(ChildActivity currentActivity, ActivityCallStack parentChain, ProcessActivityTreeOptions options, ProcessActivityCallback callback, IList1& validationErrors) at System.Activities.ActivityUtilities.CacheRootMetadata(Activity activity, LocationReferenceEnvironment hostEnvironment, ProcessActivityTreeOptions options, ProcessActivityCallback callback, IList1& validationErrors)
at System.Activities.Hosting.WorkflowInstance.ValidateWorkflow(WorkflowInstanceExtensionManager extensionManager)
at System.Activities.Hosting.WorkflowInstance.RegisterExtensionManager(WorkflowInstanceExtensionManager extensionManager)
at System.Activities.WorkflowApplication.EnsureInitialized()
at System.Activities.WorkflowApplication.Enqueue(InstanceOperation operation, Boolean push)
at System.Activities.WorkflowApplication.SimpleOperationAsyncResult.Run(TimeSpan timeout)
at System.Activities.WorkflowApplication.BeginRun(AsyncCallback callback, Object state)
at UiPath.Executor.RobotRunner.d__83.MoveNext()

bot the server configurations are the same. on analysing, i found out that the dependent packages for the project weren’t being downloaded. there are like 14 dependent packages, but only 2 of them are being downloaded along with the process folder.

i checked proxy, firewall etc and all the necessary URLs like for the orchestrator, nuget.org, gallery.uipath.com etc are whitelisted.

i tried to manually copy all the necessary packages from the QA machine and tried to run the process but yet it failed with the very same error. i am unable to find a solution for this. your help/ suggestions/ solutions highly appreciated. thanks!