No visible @interface for 'AFHTTPSessionManager' declares the selector 'POST:parameters:progress:success:failure:'

The method you are looking for is POST:parameters:success:failure:. So simply remove the progress:nil from the method call. The whole method call would be look like below.

    [manager POST:BASEURL parameters:dict success:^(NSURLSessionTask *task, id responseObject) {

        [hud hideAnimated:YES];
        // Login response validation
        if (responseObject == [NSNull null]) {
            [self showMessage:@"Login Failed" Message:@"Unable to login. Please try again!"];
        }else {
            //NSError *error = nil;
            NSLog(@"response type : %@", NSStringFromClass([responseObject class]));
            //NSDictionary *response = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:&error];
            [self checkResultValue:(NSDictionary *)responseObject];
        }

    } failure:^(NSURLSessionTask *task, NSError *error) {

        NSLog(@"AFHTTPSession Failure : %@", [error localizedDescription]);
    }];

In AFNetworking 4.0

POST:

[manager POST:baseUrl parameters:params headers:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {
} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
}];

GET:

[manager GET:baseUrl parameters:nil headers:nil progress:nil success:^(NSURLSessionDataTask * _Nonnull task, id  _Nullable responseObject) {

} failure:^(NSURLSessionDataTask * _Nullable task, NSError * _Nonnull error) {
      NSLog(@"getDeviceScanResults: failure: %@", error.localizedDescription);
}];