Error: boto3 dynamodb unable to locate credentials

The credential provider chain did not find usable AWS credentials. This happens before DynamoDB can evaluate table permissions; adding a table policy does not supply credentials to the process.

1. Select the intended AWS profile and verify it with aws sts get-caller-identity --profile work.
2. For IAM Identity Center, run aws sso login --profile work and retry.
3. In Lambda, ECS or EC2, use the runtime's IAM role and check that the process can obtain its temporary credentials.
4. Check for stale environment credentials overriding the profile. Temporary credentials require a session token as well as the access-key pair.

Keep credentials out of source code. A successful CLI command does not prove a different SDK process uses the same profile or configuration files. For Python, explicitly select the intended profile with boto3.Session(profile_name="work"). See boto3 credential providers and SSO profiles in Dynobase.