After downloading Web Transaction Analysis page view packets from AppResponse Xpert and opening AppTransaction Xpert,...

The prompt always appears when you use this workflow. It means AppResponse Xpert passed a parameter to AppTransaction Xpert, causing it to search the specified Transaction Trace Warehouse server for supporting server trace information.

The AppTransaction Xpert preferences were set to always import Transaction Trace Warehouse trace data no matter how the packets were obtained.

While importing the packets, AppTransaction Xpert noticed HTTP headers indicating the presence of transaction tracing. It is asking for the hostname and credentials of the appropriate Transaction Trace Warehouse server to download the specific transaction traces referenced in the HTTP headers of the packet trace.

When the AppInternals Xpert instrumentation is set to create trace files, it marks the TCP headers for each packet in that transaction so AppTransaction Xpert knows to look for supporting transaction data.