Unable to populate text in SAP text box after enter the T-Code

[csekharp18]

I am working on SAP process using PAD 

it is working till T-code entering after that I need to enter the text in fields but it is not working,

when I am spying the element it is getting some attributes but when I ran the flow it is giving error.

can you please help me on this issue.

Error Message :-  Failed to write in textbox (error while writing)

Error Details :-  Object reference not set to an instance of an object.: Robin.Core.ActionException: Failed to write in textbox (error while writing) ---> System.NullReferenceException: Object reference not set to an instance of an object.
at Robin.DesktopAutomationCore.ElementSearchCriteria.SearchConditions.ElementTagCondition.IsSatisfied(IElement element)
at System.Linq.Enumerable.All[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Linq.Enumerable.WhereListIterator`1.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
at Robin.DesktopAutomationCore.ElementRetraction.SearchCriteria.ElementSearchCriteria.Filter(List`1 elements)
at Robin.DesktopAutomationCore.ElementRetraction.ElementTreeWalker.FindInChildren(IElement element, LinkedListNode`1 searchCriteriaNode)
at System.Collections.Generic.List`1.ForEach(Action`1 action)
at System.Collections.Generic.List`1.ForEach(Action`1 action)
at Robin.DesktopAutomationCore.ElementRetraction.ElementTreeWalker.GetMatchingElements()
at Robin.DesktopAutomationCore.ElementRetraction.ElementRetractor.RetractAllMatchingElements(Boolean singleResult)
at Robin.Plugin.Sap.SapAutomation.<>c__DisplayClass7_0.<RetractElement>b__0()
at Robin.UIAutomationCore.Utilities.Clock.Execute[T](Int64 maxMillisecondsToWait, Int32 step, Func`1 action, Func`2 successCondition)
at Robin.Plugin.Sap.SapAutomation.RetractElement(IntPtr windowHandle, String selector, Int32 millisecondsToWait)
at Robin.Modules.UIAutomation.Actions.AutomationRuntimes.SapAutomationRuntime.RetractElement[T](IntPtr windowHandle, String selector)
at Robin.Modules.UIAutomation.Actions.AutomationRuntimes.AutomationRuntimeBase.Execute[T](IntPtr windowHandle, String selector, Action`1 action)
at Robin.Modules.UIAutomation.Actions.AutomationRuntimes.AutomationRuntimeBase.PopulateTextFieldInWindow(IntPtr windowHandle, String selector, String text)
at Robin.Modules.UIAutomation.Actions.UIAutomationActionsDispatcher.PopulateTextFieldInWindow(Variant windowSelector, Variant textFieldSelector, Variant textToFillIn, Guid windowId, Int32 automationImpl)
--- End of inner exception stack trace ---
at Robin.Modules.UIAutomation.Actions.PopulateTextFieldInWindow.Execute(ActionContext context)
at Robin.Runtime.Engine.ActionRunner.RunAction(String action, Dictionary`2 inputArguments, Dictionary`2 outputArguments, IActionStatement statement)