Please help. I am very new to RestKit and have been struggling for days to get a fairly straight forward POST successfully executed using RestKit .20.3. I follow all the various samples and instructions and used part of Alexander Edge's tutorial and the RestKit GitHub samples and documentation to no avail. Can someone take a quick glance at my code and give me some tips on what i can do to perform a successful POST using RestKit .20.3? I suspect that my last line of code is faulty because, my postObject is "nil" but, I am just not sure. Any tips or suggestions would be greatly appreciated.

BTW: The error i receive in my debug logs is "Expected status code in (400-499), got 204"

```
- (void)setupRestKitTutorial{
NSLog(@"setupRestKitTutorial - Start");

RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);
RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);

RKObjectManager *manager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:getDataURL]];
//[manager setRequestSerializationMIMEType:RKMIMETypeJSON];

//[[manager HTTPClient] setDefaultHeader:@"X-Parse-REST-API-Key" value:@"inquiryData"];
//[[manager HTTPClient] setDefaultHeader:@"X-Parse-Application-Id" value:@"inquiryData"];

//Set up Request Header
[[manager HTTPClient] setDefaultHeader:@"clientAccount" value:@"6"];
[[manager HTTPClient] setDefaultHeader:@"docType" value:@"T"];
[[manager HTTPClient] setDefaultHeader:@"userId" value:@"uid01"];
[[manager HTTPClient] setDefaultHeader:@"class" value:headerClass];
[[manager HTTPClient] setDefaultHeader:@"clientCode" value:@"02"];
[[manager HTTPClient] setDefaultHeader:@"requestType" value:@"submit"];
[[manager HTTPClient] setDefaultHeader:@"token" value:@"f3a6a4dc1c8f77d79a1a1f6a5d439933"];
[[manager HTTPClient] setDefaultHeader:@"documentNum" value:@"439299827"];
[[manager HTTPClient] setDefaultHeader:@"Content-Type" value:@"application/x-www-form-urlencoded"];

//End setup Request Header

NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
manager.managedObjectStore = managedObjectStore;

RKObjectMapping *errorMapping = [RKObjectMapping mappingForClass:[RKErrorMessage class]];

[errorMapping addPropertyMapping:[RKAttributeMapping attributeMappingFromKeyPath:nil toKeyPath:@"errorMessage"]];

RKResponseDescriptor *errorDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:errorMapping
                                                                                pathPattern:nil
                                                                                    keyPath:@"error"
                                                                                statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassClientError)];

[manager addResponseDescriptorsFromArray:@[errorDescriptor]];

NSDictionary *parentObjectMapping = @{
                                      @"inquiryStatus" : @"inquiryStatus",
                                      @"entityNo" : @"entityNo",
                                      @"docType" : @"docType",
                                      @"docNumber" : @"docNumber",
                                      @"mvNumber" : @"mvNumber",
                                      @"totalAmount" : @"totalAmount"
                                      };

RKEntityMapping *ticketParentMapping = [RKEntityMapping mappingForEntityForName:NSStringFromClass([TicketParent class]) inManagedObjectStore:manager.managedObjectStore];
ticketParentMapping.identificationAttributes = @[ @"entityNo" ];
[ticketParentMapping addAttributeMappingsFromDictionary:@{
 @"name" : @"name"
 }];
[ticketParentMapping addAttributeMappingsFromDictionary:parentObjectMapping];

/**
 Complete Core Data stack initialization
 */

[managedObjectStore createPersistentStoreCoordinator];

NSString *storePath = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"TicketParent.sqlite"];

NSError *error;

NSPersistentStore *persistentStore = [managedObjectStore addSQLitePersistentStoreAtPath:storePath fromSeedDatabaseAtPath:nil  withConfiguration:nil options:@{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES} error:&error];

NSAssert(persistentStore, @"Failed to add persistent store with error: %@", error);

// Create the managed object contexts
[managedObjectStore createManagedObjectContexts];

// Configure a managed object cache to ensure we do not create duplicate objects
managedObjectStore.managedObjectCache = [[RKInMemoryManagedObjectCache alloc] initWithManagedObjectContext:managedObjectStore.persistentStoreManagedObjectContext];

[manager postObject:nil path:@"http://www.mytesturl.com/jsonservices" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *result) {
    NSLog(@"We object mapped the response with the following result: %@", result);
} failure:nil];

```

}

Here is my updated code. I made all the suggest mods and now I am getting the following error: got 500" UserInfo=0x95c7bd0 {NSLocalizedRecoverySuggestion=Error 500: javax.servlet.ServletException: org.codehaus.jackson.map.JsonMappingException: Can not find a deserializer for non-concrete Map type [map type; class javax.ws.rs.core.MultivaluedMap, [simple type, class java.lang.String] -> [simple type, class java.lang.String]] 
Any ideas on a fix?

```
- (void)setupRestKitTutorial{
NSLog(@"setupRestKitTutorial - Start");

RKLogConfigureByName("RestKit/ObjectMapping", RKLogLevelTrace);
RKLogConfigureByName("RestKit/Network", RKLogLevelTrace);

RKObjectManager *manager = [RKObjectManager managerWithBaseURL:[NSURL URLWithString:getDataURL]];
[manager setRequestSerializationMIMEType:RKMIMETypeJSON];
[manager setAcceptHeaderWithMIMEType:@"application/x-www-form-urlencoded"];
[manager setAcceptHeaderWithMIMEType:RKMIMETypeJSON];

[RKObjectManager setSharedManager:manager];
[RKMIMETypeSerialization registerClass:[RKNSJSONSerialization class] forMIMEType:@"application/x-www-form-urlencoded"];

RKObjectMapping *userMapping = [RKObjectMapping requestMapping];
[userMapping addAttributeMappingsFromDictionary:@{@"clientAccount" : @"clientAccount",
 @"docType" : @"docType",
 @"userId" : @"userId",
 @"class1" : @"class1",
 @"clientCode" : @"clientCode",
 @"requestType" : @"requestType",
 @"token" : @"token",
 @"documentNum" : @"documentNum"}];

RKRequestDescriptor *requestDescriptor = [RKRequestDescriptor requestDescriptorWithMapping:userMapping objectClass:[RequestInquiry class]                                       rootKeyPath:nil method:RKRequestMethodPOST];

[manager addRequestDescriptor:requestDescriptor];

[[manager HTTPClient] setDefaultHeader:@"X-Parse-REST-API-Key" value:@"inquiryData"];
[[manager HTTPClient] setDefaultHeader:@"X-Parse-Application-Id" value:@"inquiryData"];

//Set up Request Header
[[manager HTTPClient] setDefaultHeader:@"clientAccount" value:@"6"];
[[manager HTTPClient] setDefaultHeader:@"docType" value:@"T"];
[[manager HTTPClient] setDefaultHeader:@"userId" value:@"uid01"];
[[manager HTTPClient] setDefaultHeader:@"class1" value:headerClass];
[[manager HTTPClient] setDefaultHeader:@"clientCode" value:@"02"];
[[manager HTTPClient] setDefaultHeader:@"requestType" value:@"submit"];
[[manager HTTPClient] setDefaultHeader:@"token" value:@"f3a6a4dc1c8f77d79a1a1f6a5d439933"];
[[manager HTTPClient] setDefaultHeader:@"documentNum" value:@"439299827"];
//[[manager HTTPClient] setDefaultHeader:@"contenttype" value:@"application/x-www-form-urlencoded"];

//End setup Request Header

NSManagedObjectModel *managedObjectModel = [NSManagedObjectModel mergedModelFromBundles:nil];
RKManagedObjectStore *managedObjectStore = [[RKManagedObjectStore alloc] initWithManagedObjectModel:managedObjectModel];
manager.managedObjectStore = managedObjectStore;

RKObjectMapping *errorMapping = [RKObjectMapping mappingForClass:[RKErrorMessage class]];

[errorMapping addPropertyMapping:[RKAttributeMapping attributeMappingFromKeyPath:nil toKeyPath:@"errorMessage"]];

RKResponseDescriptor *errorDescriptor = [RKResponseDescriptor responseDescriptorWithMapping:errorMapping
                                                                                pathPattern:nil
                                                                                keyPath:@"error"
                                                                                //statusCodes:[NSIndexSet indexSetWithIndex:200]];
                                                                                statusCodes:RKStatusCodeIndexSetForClass(RKStatusCodeClassClientError)];

[manager addResponseDescriptorsFromArray:@[errorDescriptor]];

NSDictionary *parentObjectMapping = @{
                                      @"inquiryStatus" : @"inquiryStatus",
                                      @"entityNo" : @"entityNo",
                                      @"docType" : @"docType",
                                      @"docNumber" : @"docNumber",
                                      @"mvNumber" : @"mvNumber",
                                      @"totalAmount" : @"totalAmount"
                                      };

RKEntityMapping *ticketParentMapping = [RKEntityMapping mappingForEntityForName:NSStringFromClass([TicketParent class]) inManagedObjectStore:manager.managedObjectStore];
ticketParentMapping.identificationAttributes = @[ @"entityNo" ];
[ticketParentMapping addAttributeMappingsFromDictionary:@{
 @"mvType" : @"mvType"
 }];
[ticketParentMapping addAttributeMappingsFromDictionary:parentObjectMapping];

/**
 Complete Core Data stack initialization
 */

[managedObjectStore createPersistentStoreCoordinator];

NSString *storePath = [RKApplicationDataDirectory() stringByAppendingPathComponent:@"TicketParent.sqlite"];

NSError *error;

NSPersistentStore *persistentStore = [managedObjectStore addSQLitePersistentStoreAtPath:storePath fromSeedDatabaseAtPath:nil  withConfiguration:nil options:@{NSMigratePersistentStoresAutomaticallyOption:@YES, NSInferMappingModelAutomaticallyOption:@YES} error:&error];

NSAssert(persistentStore, @"Failed to add persistent store with error: %@", error);

// Create the managed object contexts
[managedObjectStore createManagedObjectContexts];

// Configure a managed object cache to ensure we do not create duplicate objects
managedObjectStore.managedObjectCache = [[RKInMemoryManagedObjectCache alloc] initWithManagedObjectContext:managedObjectStore.persistentStoreManagedObjectContext];

// Request Object with json paramaters
RequestInquiry *requestInquiry = [[RequestInquiry alloc] init];
requestInquiry.docType = @"T";
requestInquiry.documentNum = @"439299827";
requestInquiry.clientAccount = @"6";
requestInquiry.clientCode = @"02";
requestInquiry.token = @"f3a6a4dc1c8f77d79a1a1f6a5d439933";
requestInquiry.requestType = @"submit";
requestInquiry.userId = @"uid01";
requestInquiry.class1 = @"class com.rest.client.JsonRequest";

[manager postObject:requestInquiry path:@"/RestIVR/restservices/ticketservices/jinquiry" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *ticketParentMapping)
 {
     RKLogError(@"%@",ticketParentMapping);
 }
            failure:^(RKObjectRequestOperation *operation, NSError *error)
 {
     RKLogError(@"%@",error);
 }];

```