Getting Null data from google adwords api

I want to fetch location details for all the ads from google adwords but I am getting null entries.I am not able to get any data from adwords api .Help me in That as according to my knowledge there is not problem with my code and I am not able to find any solution for that.My code that I have tried is written below.

 public void GetLocationAds()             {                 AdWordsUser user = new AdWordsUser();                 {                     try                     {                         int offset = 0;                                                                 // Create selector.                         using (CampaignCriterionService campaignCriterionService =                             (CampaignCriterionService)user.GetService(AdWordsService.v201809.CampaignCriterionService))                         {                             Selector selector = new Selector()                             {                                 fields = new string[]                              {                                   CampaignCriterion.Fields.CampaignId,                                     CampaignCriterion.Fields.CampaignCriterionStatus,                                      //Location.Fields.LocationName,                                      //Location.Fields.CriteriaType,                                      //Location.Fields.ParentLocations,                                      //LocationCriterion.Fields.CanonicalName,                                      //LocationCriterion.Fields.CountryCode,                                   CampaignCriterion.Fields.IsNegative,                              },                            //     predicates = new Predicate[]                            //{                            //    Predicate.Equals( "CriteriaType","LOCATION"),                            //},                                 paging = Paging.Default,                                 ordering = new OrderBy[]                        {                                 OrderBy.Asc(  CampaignCriterion.Fields.CampaignId)                        }                             };                             CampaignCriterionPage page = new CampaignCriterionPage();                             do                             {                                 // Get the ad groups.                                  page = campaignCriterionService.get(selector);                                 // Display the results.                                 if (page != null && page.entries != null)                                 {                                     int j = selector.paging.startIndex;                                     foreach (CampaignCriterion campaignCriterion in page.entries)                                     {                                         var campaignId = campaignCriterion.campaignId;                                         bool IsLocation = campaignCriterion.isNegative;                                         var CampaignCriterionType = campaignCriterion.CampaignCriterionType;                                     }                                 }                                 else                                 {                                     Console.Write("No campaignCriterion were found.");                                 }                                 selector.paging.IncreaseOffset();                             }                             while (selector.paging.startIndex < page.totalNumEntries);                         }                     }                     catch (Exception ex)                     {                     }                 }             } 

Kindly help me in that.