How to take a screenshot of a "closed" Win 2008 terminal session?

Question

Windows Server

Hello! There is a server on Win 2008, an account with full rights has been set up, it is necessary to send a screenshot of the screen at a certain time to the mail and without a permanent presence on the server. Everything necessary has been done, the software "creating-sending" the screen works as it should, but if I'm NOT (disconnected from the server) at the terminal session, then the screen comes just white, most likely when I disconnect from the server, "Windows does not draw the image itself ". The question is actually the following, how to get a full-fledged screenshot from the active user session on the server?