How to avoid IE Navigation error which says the RPC server is unavailable?

I have a service which is installed on my server. It suddenly stops with the following error log:

  The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)   at System.RuntimeType.InvokeDispMethod(String name, BindingFlags invokeAttr, Object target, Object[] args, Boolean[] byrefModifiers, Int32 culture, String[] namedParameters)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at Microsoft.VisualBasic.CompilerServices.VBBinder.InvokeMember(String name, BindingFlags invokeAttr, Type objType, IReflect objIReflect, Object target, Object[] args, String[] namedParameters)
   at Microsoft.VisualBasic.CompilerServices.LateBinding.InternalLateCall(Object o, Type objType, String name, Object[] args, String[] paramnames, Boolean[] CopyBack, Boolean IgnoreReturn)
   at Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateCall(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack, Boolean IgnoreReturn)
   at vbIranStock.VBNetLib.vbScript4.Parsing(Object& objIE, Object& MainHTML, String[]& logid, String& logpath, String& Servicepath, Boolean& doPrint) in vbScript4.vb:line 119
   at vbIranStock.VBNetLib.vbScript4.VbsRun4(Boolean doPrint) in vbScript4.vb:line 50
   at WindowsServiceVB.Service1.MyProgram() in Service1.vb:line 106
   at WindowsServiceVB.Service1.ScheduleService() in Service1.vb:line 73

When I refer to the specified Visual Basic code line, I see following codes:

119:  objIE.Navigate("https://www.example.ir" + lblUrl)

I checked following RPC related services which all are running and are not stopped:

Remote Process Call
Remote Process Call Locator
DeCom Server Process Launcher
RPC Endpoint Mapper
Remote Access Connection Manager
Remote Access Auto Connection Manager
Remote Registry

Besides I checked firewall and added inbound and outbound rules to allow my service connection. But again I have this error. Please help me to stop getting the error.