data not display when click on auto complete text box angular 7

I work on angular 7 project

I face issue I can't display option Name when click on auto complete textbox

so when click on auto complete text box it not display any thing and not show data related to option Name

and that actually my issue

so How to solve this issue

constructor(private http: HttpClient,private _dataService: DeliverySysService) {  
    this._dataService.getExport().subscribe(data => { this.ExportOptions = data   
        console.log(this.ExportOptions)  
    });  
  
this display data  as below :  
  
(5) [{…}, {…}, {…}, {…}, {…}]  
0: {optionID: 1, optionName: "Export"}  
1: {optionID: 2, optionName: "Export Normalized"}  
2: {optionID: 3, optionName: "Export Normalized New"}  
3: {optionID: 4, optionName: "Export Normalized Relation"}  
4: {optionID: 5, optionName: "Export Nxp Comptitor"}  

Now use ng -autocomplete tool so I do the following :

on Delivery System Component html component

class="ng-autocomplete" style="width:300px; z-index: 5;">  
        "exportOptions" [initialValue]="" [searchKeyword]="keyword" [placeHolder]="placeholder"  
          [itemTemplate]="itemTemplate" [notFoundTemplate]="notFoundTemplate" notFoundText="Not found"  
          (selected)='selectEvent($event)' (inputChanged)='onChangeSearch($event)'>  
          
          
          "item.Text">  
          
          
          "notFound">