System.NullReferenceException: Object reference not set to an instance of an object. at RMuseum.Services.Implementation.GanjoorService.GetTajikPageByUrlAsync(String url, Boolean catPoems) in C:\Users\hamidreza\source\repos\ganjoor\GanjoorService\RMuseum\Services\Implementation\GanjoorService-Partials\GanjoorService-Tajik.cs:line 49