I have a 2008R2 Terminal Server, sometimes when users connect from outside (never internal) they get prompted for the credentials and then presented with a black screen that after 2-5 seconds disconnects them.
I am seeing no errors in applications, but occasionally event ID 50 & 56 in system.
All windows update, latest drivers and bios.
Tried various fixes including disabling RSS & Chimney from TCP.
If when the black screen appears you press CTRL-ALT-END, the desktop appears and you can carry on as normal!
Any suggestions welcome..