Стенды: (и виртуальные, и реальный)
ALT K Workstation 11.0 (обновленный до Sisyphus)
ALT K Workstation 11.0
ALT Workstation 11.0

Версия: xpra-6.2.3

$ xpra start :101
Entering daemon mode; any further errors will be reported to:
  '/run/user/1000/xpra/101/server.log.new'
Actual log file name is now: '/run/user/1000/xpra/101/server.log'

$ xpra list
Found the following xpra sessions:
/run/user/1000/xpra/101:
	UNKNOWN session at :101
/run/user/1000/xpra:
	UNKNOWN session at :101
/home/test/.xpra:
	UNKNOWN session at :101
Re-probing unknown sessions in: /run/user/1000/xpra, /home/test/.xpra, /run/user/1000/xpra/101

	UNKNOWN session at :101 (cleaned up)
	UNKNOWN session at :101 (cleaned up)
	UNKNOWN session at :101 (cleaned up)


При подключении по ssh:
$ xpra attach ssh://test@10.4.160.148/101 --max-size=1200x800 --clipboard-direction=both --clipboard=yes --opengl=no
2025-04-16 19:42:55,030  SSH: 'server socket for display 101 is in UNKNOWN state'
2025-04-16 19:42:55,031  SSH: ' waiting up to 20 seconds'
2025-04-16 19:43:15,111  SSH: 'xpra initialization error:'
2025-04-16 19:43:15,111  SSH: ' cannot find live server for display 101'
2025-04-16 19:43:15,112 SSH EOF on stderr of run-xpra
2025-04-16 19:43:15,112 Error: failed to receive anything, not an xpra server?
2025-04-16 19:43:15,112   could also be the wrong protocol, username, password or port
2025-04-16 19:43:15,112   or the session was not found
2025-04-16 19:43:15,112 Connection failed

Ошибка воспроизводится в p11, в задании p11#377185 и в Sisyphus