aws CloudFormationスタックの作成 エラー

Question

CloudFormationでVPC,SG,IGW,SubnetのコードをVscodeで書きAWSのCloudFormation でスタックの作成をしようとしたのですが、下記のエラーがでてしまい困っています。
ご教授お願い致します。

エラー内容
Template format error: Unresolved resource dependencies [hebiishiPrivatesubnet2a] in the Resources block of the template

コード
AWSTemplateFormatVersion: "2010-09-09"

Resources: 
  XXXVPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: 10.0.0.0/16
      EnableDnsHostnames: true
      EnableDnsSupport: true
      Tags:
        - Key: Name
          Value: XXX-VPC

  XXXpublicsubnet2a:
    Type: AWS::EC2::Subnet
    Properties:
      AvailabilityZone: ap-northeast-2a
      VpcId: !Ref XXXVPC
      CidrBlock: 10.0.1.0/24
      MapPublicIpOnLaunch: true 
      Tags:
        - Key: Name
          Value: XXXpublicsubnet2a

  XXXpublicsubnet1c:
    Type: AWS::EC2::Subnet
    Properties:
      AvailabilityZone: ap-northeast-1c
      VpcId: !Ref XXXVPC
      CidrBlock: 10.0.2.0/24
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: XXXpublicsubnet1c

  XXXprivatesubnet2a:
    Type: AWS::EC2::Subnet
    Properties:
      AvailabilityZone: ap-northeast-2a
      VpcId: !Ref XXXVPC
      CidrBlock: 10.0.3.0/24
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: XXXprivatesubnet2a

  XXXprivatesubnet2c:
    Type: AWS::EC2::Subnet
    Properties:
      AvailabilityZone: ap-northeast-2c
      VpcId: !Ref XXXVPC
      CidrBlock: 10.0.4.0/24
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: XXXprivatesubnet2c

  XXXIGW:
    Type: "AWS::EC2::InternetGateway"
    Properties:
      Tags:
      - Key: Name
        Value: XXX-IGW

  AttachGateway:
    Type: "AWS::EC2::VPCGatewayAttachment"
    Properties:
      InternetGatewayId: !Ref XXX-IGW
      VpcId: !Ref XXXVPC

  XXXrtbpublicsubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref XXXVPC
      Tags:
        - Key: Name
          Value: XXXrtpublicsubnet

  XXXRoutePublic:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref XXX-rtb-publicsubnet
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref XXXIGW

  XXXrtbprivatesubnet:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref XXXVPC
      Tags:
        - Key: Name
          Value: XXXrtbprivatesubnet


  XXXRouteTableAssocPublic2a:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref XXXpublicsubnet2a
      RouteTableId: !Ref XXXrtbpublicsubnet

  XXXRouteTableAssocPublic2c:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref XXXpublicsubnet2c
      RouteTableId: !Ref XXXrtbpublicsubnet

  XXXRouteTableAssocPrivate2a:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref XXXPrivatesubnet2a
      RouteTableId: !Ref XXXrtbprivatesubnet

  XXXRouteTableAssocPrivate2c:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      SubnetId: !Ref XXX-Privatesubnet2c
      RouteTableId: !Ref XXXrtbprivatesubnet