Here is what we do to kill the orphan sessions to make room.
C:\Users\CyberArkDBA>qwinsta /server:parisdb02p
SESSIONNAME USERNAME ID STATE TYPE DEVICE
services 0 Disc
console 1 Conn
CyberArkDBA 9 Disc
31c5ce94259d4... 65536 Listen
rdp-tcp 65537 Listen
C:\Users\CyberArkDBA>rwinsta 9 /server:parisdb02p /V
C:\Users\CyberArkDBA>qwinsta /server:parisdb02p
SESSIONNAME USERNAME ID STATE TYPE DEVICE
services 0 Disc
console 1 Conn
31c5ce94259d4... 65536 Listen
rdp-tcp 65537 Listen