ExpiredToken

Expired Token Error in AWS often has a different root cause depending on whether it occurs in development, staging, or production — because these environments commonly have different IAM roles, VPC configurations, and security group rules. Resources in different AWS accounts require cross-account IAM roles: the resource account must have a resource policy or role that trusts the calling account, and the calling account must have a role that allows sts:AssumeRole. If these conditions are only configured for production, the same code fails in development. Region-specific causes: some AWS services are only available in specific regions (e.g., Amazon Bedrock, certain EC2 instance types), and SDK calls without an explicit region parameter use the default region, which may not have the service. VPC routing: resources in private subnets need a VPC endpoint or NAT gateway to reach AWS service endpoints — without these, API calls time out with errors resembling Expired Token Error. Use aws configure list to verify the active profile and region before debugging.