After the configuration of AmazonConnectionResource, test the connection with Amazon S3 service. The test connection is successful message will be displayed.
Then configure the Amazon s3 activity in Businessworks Process and execute the same:
Execution console will show following error message.
"com.amazonaws.services.s3.model.AmazonS3Exception: Access Denied"

Follow the given steps

======================= Product: TIBCO ActiveMatrix BusinessWorks Plug-in for Amazon S3 Version: 6.4.x ========================

If the federated Amazon account is configured with Amazon S3 service then check access permission for the federated user for the service.
If the access permissions are given then to resolve this issue configure Cross-Account Access in "AmazonConnectionResource".
Cross Account Access will configure the access for the BW AWS S3 plugin.

================
Cross Account Access:
Use the AWS Security Token Service (AWS STS) to create and provide trusted users with temporary security credentials that can control access to your AWS resources. This parameter uses cross-account access temporary security credentials created by AssumeRole. Please refer AWS documentation for further details on Temporary Security Credentials.
================

For more details please go through:

https://docs.tibco.com/pub/bwpluginawss3/6.4.0/doc/html/GUID-9BF8A103-A43B-4807-AB8B-55E71092BC5A.html