When using the DX UIM AWS probe (specifically version 23.4.3 or earlier) on a hub hosted within the AWS cloud, the probe may fail to validate credentials. This occurs even when IAM Role Based Authentication is enabled and correctly configured on the host EC2 instance.
A product defect was identified where the probe attempted to parse all AWS regions simultaneously during the validation process. This behavior led to internal timeouts and caused the "Test Connection" functionality to fail even if the credentials were valid for a specific region.
The issue will be fixed in a new AWS probe version (after 6.0).