You are asked by RWS Support to save and send the Stacktrace of the error message you receive in Trados Studio.
This file usually contains more details about the error and can speed up the investigation of the issue.

Usually, on the error message pop-up, there is a small Save icon, as you can see below:



Click the icon and save the generated "[abc].sdlerror.xml" file to your computer.
This is the file RWS Support needs - attach it to your ticket or to the email thread for the ticket.