Fix AWS CDK Cross-Stack Reference Error

The error Error: Stack "exampleStack1" cannot consume a cross reference from stack "exampleStack2". Cross stack references are only supported for stacks deployed to the same environment or between nested stacks and their parent stack likely happens if you do the following:

1. You try to reference another stack that is in a different AWS region. Note: cross region references aren't supported.
2. You aren't passing region and account values in the env of the StackProps.

In order to fix the error in AWS CDK, you need to add the env with region and account parameters to the stack when you create it as shown in the code example below:

new exampleStack1(
  app, 'exampleStack1', {
    env: {
      region: 'eu-west-1',
      account: '012345678910',
    },
  });
}