خطا در فراخوانی متد Get

سلام من وقتی متد Get به همراه ID فراخوانی میکنم خطای 500 زیر رخ میده:

System.InvalidOperationException: The type of navigation 'Customer.Orders' is 'IQueryable<Order>' for which it was not possible to create a concrete instance. Either initialize the property before use, add a public parameterless constructor to the type, or use a type which can be assigned a 'HashSet<>' or 'List<>'.

   at Microsoft.EntityFrameworkCore.Metadata.Internal.ClrICollectionAccessor`3.GetOrCreateCollection(Object instance, Boolean forMaterialization)

   at Microsoft.EntityFrameworkCore.Metadata.Internal.ClrICollectionAccessor`3.GetOrCreate(Object entity, Boolean forMaterialization)

   at Microsoft.EntityFrameworkCore.Query.RelationalShapedQueryCompilingExpressionVisitor.ShaperProcessingExpressionVisitor.InitializeIncludeCollection[TParent,TNavigationEntity](Int32 collectionId, QueryContext queryContext, DbDataReader dbDataReader, SingleQueryResultCoordinator resultCoordinator, TParent entity, Func`3 parentIdentifier, Func`3 outerIdentifier, INavigationBase navigation, IClrCollectionAccessor clrCollectionAccessor, Boolean trackingQuery, Boolean setLoaded)

   at lambda_method25(Closure , QueryContext , DbDataReader , ResultContext , SingleQueryResultCoordinator )

   at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable`1.AsyncEnumerator.MoveNextAsync()

   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable`1 asyncEnumerable, CancellationToken cancellationToken)

   at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable`1 asyncEnumerable, CancellationToken cancellationToken)

   at EshopApi.Servises.Implementation.CustomerRepository.Find(Int32 id) in C:\Users\Mohammad\source\repos\EshopApi\EshopApi\Servises\Implementation\CustomerRepository.cs:line 29

   at EshopApi.Controllers.CustomersController.GetCustomer(Int32 id) in C:\Users\Mohammad\source\repos\EshopApi\EshopApi\Controllers\CustomersController.cs:line 34

   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Logged|12_1(ControllerActionInvoker invoker)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)

   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)

   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)

   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)

   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)

   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)

   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

متد تعریف شده در کنترولر:

        public async Task<IActionResult> GetCustomer([FromRoute] int id)
        {
            var customer = await _customer.Find(id);
            return Ok(customer);
        }

کد repository

        public async Task<Customer> Find(int id)
        {
            return await _db.Customers.Include(x=>x.Orders).SingleOrDefaultAsync(i => i.Id == id);
        }