Referencing the output of Parent stack in nested stack - Cloudformation

I am trying to create the nested stack but having trouble as I am new to this and still in learning process. I have created the vpc with 2 private and 2 public subnets. Then attached the internet-facing elb to 2 public subnets. I think I am not referencing it right. Vpc is created but while creating elb there is an error Output 'VpcID' not found in stack I think there might be a problem in the syntax as I am changing my previous file to nested stack. I might not be referencing right in the Internet facing elb stack.

Root stack:

---AWSTemplateFormatVersion: 2010-09-09Parameters:  bucketname:    Type: String    Description: Path to the bucket    Default: wahaj-webserver  bucketpath:    Type: String    Description: Path to the bucket    Default: /nested-stackResources:  Vpcstack:    Type: AWS::CloudFormation::Stack    Properties:      TemplateURL: !Sub "https://${bucketname}.s3.us-east-2.amazonaws.com${bucketpath}/vpc1.yml"  elb:    DependsOn: Vpcstack    Type: AWS::CloudFormation::Stack    Properties:      TemplateURL: !Sub "https://${bucketname}.s3.us-east-2.amazonaws.com${bucketpath}/internetfacing-elb.yml"      Parameters:        SubnetA: !GetAtt Vpcstack.Outputs.SubnetA        SubnetB: !GetAtt Vpcstack.Outputs.SubnetB        VpcID: !GetAtt Vpcstack.Outputs.VpcID

Vpc stack:

---AWSTemplateFormatVersion: 2010-09-09Resources:  VPC:    Type: AWS::EC2::VPC    Properties:      CidrBlock: 11.0.0.0/16      EnableDnsSupport: true      EnableDnsHostnames: true      InstanceTenancy: default  InternetGateway:    Type: AWS::EC2::InternetGateway  VPCGatewayAttachment:    Type: AWS::EC2::VPCGatewayAttachment    Properties:      VpcId: !Ref VPC      InternetGatewayId: !Ref InternetGateway  SubnetA:    Type: AWS::EC2::Subnet    Properties:      AvailabilityZone: us-east-2a      VpcId: !Ref VPC      CidrBlock: 11.0.0.0/24      MapPublicIpOnLaunch: true  SubnetB:    Type: AWS::EC2::Subnet    Properties:      AvailabilityZone: us-east-2b      VpcId: !Ref VPC      CidrBlock: 11.0.1.0/24      MapPublicIpOnLaunch: true  SubnetC:    Type: AWS::EC2::Subnet    Properties:      AvailabilityZone: us-east-2a      VpcId: !Ref VPC      CidrBlock: 11.0.2.0/24      MapPublicIpOnLaunch: false  SubnetD:    Type: AWS::EC2::Subnet    Properties:      AvailabilityZone: us-east-2b      VpcId: !Ref VPC      CidrBlock: 11.0.3.0/24      MapPublicIpOnLaunch: false  RouteTable:    Type: AWS::EC2::RouteTable    Properties:      VpcId: !Ref VPC  RouteTable2:    Type: AWS::EC2::RouteTable    Properties:      VpcId: !Ref VPC  InternetRoute:    Type: AWS::EC2::Route    DependsOn: VPCGatewayAttachment    Properties:      DestinationCidrBlock: 0.0.0.0/0      GatewayId: !Ref InternetGateway      RouteTableId: !Ref RouteTable  SubnetARouteTableAssociation:    Type: AWS::EC2::SubnetRouteTableAssociation    Properties:      RouteTableId: !Ref RouteTable      SubnetId: !Ref SubnetA  SubnetBRouteTableAssociation:    Type: AWS::EC2::SubnetRouteTableAssociation    Properties:      RouteTableId: !Ref RouteTable      SubnetId: !Ref SubnetB  SubnetCRouteTableAssociation:    Type: AWS::EC2::SubnetRouteTableAssociation    Properties:      RouteTableId: !Ref RouteTable2      SubnetId: !Ref SubnetC  SubnetDRouteTableAssociation:    Type: AWS::EC2::SubnetRouteTableAssociation    Properties:      RouteTableId: !Ref RouteTable2      SubnetId: !Ref SubnetD  SecurityGroup:    Type: AWS::EC2::SecurityGroup    Properties:      GroupName: "Internet Group"      GroupDescription: "SSH traffic in, all traffic out."      VpcId: !Ref VPC      SecurityGroupIngress:        - IpProtocol: tcp          FromPort: "22"          ToPort: "22"          CidrIp: 0.0.0.0/0      SecurityGroupEgress:        - IpProtocol: -1          CidrIp: 0.0.0.0/0  NAT:    Type: AWS::EC2::NatGateway    Properties:      AllocationId:        Fn::GetAtt:          - EIP          - AllocationId      SubnetId:        Ref: SubnetA      Tags:        - Key: Name          Value: wahaj-nat  EIP:    DependsOn: VPCGatewayAttachment    Type: AWS::EC2::EIP    Properties:      Domain: VPC  Route:    Type: AWS::EC2::Route    Properties:      RouteTableId:        Ref: RouteTable2      DestinationCidrBlock: 0.0.0.0/0      NatGatewayId:        Ref: NATOutputs:  VpcID:    Description: VPC id    Value: !Ref VPC    Export:      Name: "VpcID"  SubnetA:    Description: public subnet    Value: !Ref SubnetA    Export:      Name: "SubnetA"  SubnetB:    Description: public subnet 2    Value: !Ref SubnetB    Export:      Name: "SubnetB"  SubnetC:    Description: priavte subnet    Value: !Ref SubnetC    Export:      Name: "SubnetC"  SubnetD:    Description: private subnet 2    Value: !Ref SubnetD    Export:      Name: "SubnetD"

Internet facing elb:

---AWSTemplateFormatVersion: 2010-09-09Resources:  wahajelb:    Type: AWS::EC2::SecurityGroup    Properties:      GroupName: wahaj-elb      VpcId:        Fn::ImportValue: "VpcID"      SecurityGroupIngress:        - IpProtocol: tcp          FromPort: 22          ToPort: 22          CidrIp: 0.0.0.0/0          Description: For traffic from Internet        - IpProtocol: tcp          FromPort: 80          ToPort: 80          CidrIp: 0.0.0.0/0          Description: For traffic from Internet      GroupDescription: Security Group for demo server  MyLoadBalancer:    Type: AWS::ElasticLoadBalancing::LoadBalancer    Properties:      Listeners:        - LoadBalancerPort: "80"          InstancePort: "80"          Protocol: HTTP      SecurityGroups:        - !Ref wahajelb      LoadBalancerName: wahajelb      Subnets:        - Fn::ImportValue: "SubnetA"        - Fn::ImportValue: "SubnetB"      HealthCheck:        Target: HTTP:80/SamplePage.php        HealthyThreshold: "3"        UnhealthyThreshold: "5"        Interval: "30"        Timeout: "5"Outputs:  ec2:    Description: ec2    Value: !Ref MyLoadBalancer    Export:      Name: "MyLoadBalancer"  lgsg:    Description: lg-sg    Value: !GetAtt wahajelb.GroupId    Export:      Name: "lgsg"