I have a problem with multiple Security Groups in CloudFormation - amazon-web-services

Question

I am trying to select two Security Groups, one is from parameters and other is a new one.
But getting below errors. How can I solve this?
AWSTemplateFormatVersion : 2010-09-09
Description: "simple web layer"
Parameters:
ImageId:
Description: 'web Layer'
Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>'
AllowedPattern: "^[a-zA-Z][-a-zA-Z0-9]*$"
Default: ami-244333
Vpc:
Description: enter vpc
Type: List<AWS::EC2::VPC::Id>
Securitycab:
Type: String
Default: 0.0.0.0/0
Description: enter vpc ip range
Subnets:
Description: enter subnet
Type: List<AWS::EC2::Subnet::Id>
Default: subnet-384736383838
Securitygroup:
Description: enter sc
Type: List<AWS::EC2::SecurityGroup::Id>
Default: sg-237377383773873
Resources:
Lpsecurity:
Type: AWS::EC2::SecurityGroup
Properties:
VpcId: vpc-1a2b3c4d
GroupDescription: Sample target security group
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 80
ToPort: 80
CidrIp: !Ref Securitycab
MyEC2Instance1:
Type: 'AWS::EC2::Instance'
Properties:
ImageId: !Ref ImageId
InstanceType: t2.large
VpcId: !Ref Vpc
SubnetId: !Select [ 0, !Ref Subnets ]
SecurityGroupIds:
- !Ref Securitygroup
!Ref Lpsecurity
Error : Unsolved Resource dependence [Securitygroup !Ref Lpsecurity] in the resource block of the template.

Answer 1

A list should have dashes before every element.
Here is the suggested code from your other I have a problem in cloud formation. Error when using Fn::Join with a parameter question:
SecurityGroupIds:
- !GetAtt Securitygroup.GroupId
- !GetAtt Lpsecurity.GroupId
Alternatively, you could possibly use:
SecurityGroupIds:
- !Ref Securitygroup
- !Ref Lpsecurity