100days of Cloud(AWS) - Task 3 create named subnet under default VPC

Cloud AWS
#1

While creating subnet in default VPC , I get error as follows:
“CIDR Address overlaps with existing Subnet CIDR.” error while creating subnet?

I tried the following steps:

  1. locate default VPC id:
    aws ec2 describe-vpcs --filters Name=is-default,Values=true --query “Vpcs[0].VpcId”

2.Check available cidr range under this vpc id:

aws ec2 describe-subnets --filters Name=vpc-id,Values= --query ‘Subnets[*].{SubnetId:SubnetId,CidrBlock:CidrBlock,AvailableIpCount:AvailableIpAddressCount}’

in total 6 cidr blocks with 4091 available IP counts under each block were available in the specified / default vpc.
i did refer Interactive visual CIDR and IP range calculator - cidr.xyz cidr.xyz

still i get “CIDR Address overlaps with existing Subnet CIDR.” error while creating subnet?

how to address this error ?

#2

This forum post has a good summary of how to find a subnet that does not clash with an existing subnet. See if it helps you.