Traffic when access S3 using AWS console

When you upload a file using the AWS S3 console, the file is transferred to S3 servers located in the AWS Region you selected for your bucket. The initial interaction happens through the S3 console at s3.console.aws.amazon.com, where you choose the bucket and initiate the upload process. However, the actual data transfer of the file occurs between your computer and the Amazon S3 endpoint specific to the region where your bucket is located e.g. s3.ap-southeast-2.amazonaws.com

Regarding your firewall, I would ensure that it allows traffic to both s3.console.aws.amazon.com for accessing the S3 management console and the specific S3 endpoint for your bucket's region. That way both the access to the console and the subsequent data transfer to the S3 bucket are permitted

Check out this other post here https://repost.aws/knowledge-center/s3-could-not-connect-endpoint-url and AWS documentation for more information https://docs.aws.amazon.com/prescriptive-guidance/latest/migration-perimeter-zone-apps-network-firewall/best-practices.html https://aws.amazon.com/s3/security/