AccessDenied: User is not authorized
This error matches known, documented patterns with reliable solutions.
Quick Fix (Most Common Solution)
- Add required permissions to IAM role/user
- Check resource policies
Seeing "AccessDenied: User is not authorized"? This error can be frustrating, but it's usually fixable. It typically affects your development workflow or system. Below you'll find clear, step-by-step solutions to resolve this issue.
What This Error Means
Your AWS credentials lack permission for this action.
Frequently documented in developer and vendor support forums.
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Common Causes
- Missing IAM policy
- Resource-based policy blocking
- SCP restriction
How to Fix
- Add required permissions to IAM role/user
- Check resource policies
- Verify service control policies
Last reviewed: April 2026 How we review solutions
Environment Differences
Local Development vs AWS Lambda Execution Environments
Accessdenied Error that appears only when deployed to Lambda but not locally occurs because the Lambda execution environment differs from a developer's machine in ways that are easy to overlook.
Lambda-specific differences: the runtime filesystem is read-only except /tmp (512 MB limit). The execution environment is a microVM with limited CPU and memory that resets between invocations (or is shared for warm starts). Temporary credentials from the Lambda execution role expire every hour — code that caches credentials indefinitely will encounter auth errors after the first hour. File paths must use /tmp for any write operations — absolute paths to home directories fail. Binary dependencies (native modules, compiled tools) must be compiled for Amazon Linux 2 (Lambda's OS), not macOS or Ubuntu — use Lambda layers or Docker to compile dependencies in the correct environment. Lambda-specific environment variables (LAMBDA_TASK_ROOT, AWS_EXECUTION_ENV) indicate the runtime context. Use AWS SAM CLI or LocalStack to run Lambda locally with an environment closer to production.Optional follow-up
Some users ask whether saving fixes for recurring errors would be useful when the same issue appears again.
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Frequently Asked Questions
How do I debug IAM?
Use IAM Policy Simulator or CloudTrail logs.
What is least privilege?
Grant only permissions needed for the task.
Also Known As
- AWS error
- Amazon Web Services error
- Cloud service error
- AWS API error
Common Search Variations
- "aws access denied fix"
- "aws api error solution"
- "aws cli not working"
- "aws service error"
- "fix aws credentials error"
- "aws deployment failed"
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