Your international organization utilizes AWS CloudFormation to manage its IT infrastructure on the AWS Cloud. In the us-east-1 Region, an employee has created a CloudFormation stack named 'Application1' and has defined an exported output called 'ELBDNSName'. Concurrently, another employee in the us-east-2 Region has created a separate CloudFormation stack for another application called 'Application2' and has also defined an exported output with the name 'ELBDNSName'. When the first employee attempted to deploy the 'Application1' CloudFormation stack in the us-east-2 Region, an error was encountered. What is the cause of this error?