A developer using the AWS Management Console terminated an EC2 instance located in the us-east-1a availability zone. The EBS (Elastic Block Store) volume that was attached to this instance remains available and can be attached to other instances. Your colleague has launched a new Linux EC2 instance in the us-east-1e availability zone and is trying to attach the aforementioned EBS volume to this new instance. However, they are unable to do so and have asked for your assistance.

What explanation would you provide to your colleague regarding why they cannot attach the EBS volume to the new instance?