Fixing the Amazon Bedrock NotAuthorized 400 Error Code

 

Fixing the Amazon Bedrock NotAuthorized 400 Error Code

Question

"I received an Amazon Bedrock NotAuthorized 400 Error Code. How do I fix this?"

Clarifying the Issue

This error occurs when your AWS Identity and Access Management (IAM) permissions do not allow you to perform a specific action within Amazon Bedrock. It typically happens when you attempt to invoke a model, list models, or perform other operations without the required permissions.

The error message may look like this:

NotAuthorized  
You do not have permission to perform this action.  
HTTP Status Code: 400

Why It Matters

Amazon Bedrock provides access to foundation models for AI and machine learning applications, but it is tightly controlled through IAM permissions. If your IAM policy is missing the required permissions, your application or CLI commands will fail, preventing you from using Bedrock’s capabilities.

Fixing this error ensures that you can invoke models, manage AI workflows, and build AI-powered applications without unnecessary roadblocks.

Key Terms

• Amazon Bedrock – A managed AWS service that provides access to various foundation models (FMs) from different providers.
• IAM (Identity and Access Management) – AWS’s system for managing permissions and access to services.
• IAM Role – A set of permissions assigned to an entity (such as a user or service) in AWS.
• Policy Document – A JSON-based set of permissions that define what actions an IAM user or role can perform.
• STS (Security Token Service) – AWS service that grants temporary security credentials.

Steps at a Glance

1. Check your IAM permissions – Ensure your role or user has the correct policies attached.
2. Review AWS Bedrock Required Permissions – Confirm you have the necessary actions in your IAM policy.
3. Verify Role and Trust Policy – If using a role, ensure it's assumed by the correct service or user.
4. Use STS to Verify Identity – Check if your session has the required permissions.
5. Enable Logging for Debugging – Use AWS CloudTrail and IAM policy simulator to diagnose issues.

Detailed Steps

1.  Check Your IAM Permissions

Amazon Bedrock actions require specific IAM permissions. Run the following AWS CLI command to check your current IAM permissions:

aws iam list-attached-user-policies --user-name YourUserName

Or, if using a role:

aws iam list-attached-role-policies --role-name YourRoleName

If no relevant Bedrock permissions are listed, you need to update your IAM policy.

2.  Review AWS Bedrock Required Permissions

Ensure your IAM policy includes the required permissions. If you need full access, attach the following managed policy:

JSON

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "bedrock:*",
            "Resource": "*"
        }
    ]
}

Alternatively, for more restricted access, you can specify individual actions:

JSON

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "bedrock:InvokeModel",
                "bedrock:ListFoundationModels"
            ],
            "Resource": "*"
        }
    ]
}

3.  Verify Role and Trust Policy

If you’re using an IAM role, check the trust policy to ensure it allows the correct users or services to assume the role. Run the following command to inspect your role's trust policy:

aws iam get-role --role-name YourRoleName

Ensure the trust policy allows Bedrock actions:

JSON

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "bedrock.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

4.  Use STS to Verify Identity

Run the following AWS CLI command to check the active permissions for your session:

aws sts get-caller-identity

This ensures that your IAM user or role is correctly authenticated.

5.  Enable Logging for Debugging

Use AWS CloudTrail to track API calls and troubleshoot permission issues:

• Open AWS CloudTrail in the AWS Console.
• Search for bedrock API calls in the event history.
• Look for Access Denied errors or missing permissions.

Additionally, you can simulate IAM permissions using:

aws iam simulate-principal-policy \
    --policy-source-arn arn:aws:iam::ACCOUNT_ID:role/YourRoleName \
    --action-names "bedrock:InvokeModel"

Replace ACCOUNT_ID and YourRoleName with the actual values.

Conclusion

The NotAuthorized 400 error in Amazon Bedrock usually occurs due to missing IAM permissions. To resolve it, ensure your IAM user or role has the necessary policies, review trust policies, and use AWS logging tools for debugging. Once fixed, you’ll be able to seamlessly use Amazon Bedrock for AI model invocations and other operations. 🚀

Need AWS Expertise?

If you're looking for guidance on Amazon Bedrock or any cloud challenges, feel free to reach out! We'd love to help you tackle AWS projects. 🚀

Email us at: info@pacificw.com

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