ERROR Playout Service

all systems run without problems, only the playout service cannot be started. in the syslog I find an entry that indicates a problem with Pyhton. Even a new installation did not change anything.
can someone help me with this problem?

Dec 2 10:57:37 serverXY libretime-playout[34781]: Traceback (most recent call last):
Dec 2 10:57:37 serverXY libretime-playout[34781]: File “/usr/local/bin/libretime-playout”, line 5, in
Dec 2 10:57:37 serverXY libretime-playout[34781]: from libretime_playout.main import cli
Dec 2 10:57:37 serverXY libretime-playout[34781]: File “/usr/local/lib/python3.8/dist-packages/libretime_playout/main.py”, line 24, in
Dec 2 10:57:37 serverXY libretime-playout[34781]: from .message_handler import MessageListener
Dec 2 10:57:37 serverXY libretime-playout[34781]: File “/usr/local/lib/python3.8/dist-packages/libretime_playout/message_handler.py”, line 75, in
Dec 2 10:57:37 serverXY libretime-playout[34781]: class MessageListener:
Dec 2 10:57:37 serverXY libretime-playout[34781]: File “/usr/local/lib/python3.8/dist-packages/libretime_playout/message_handler.py”, line 79, in MessageListener
Dec 2 10:57:37 serverXY libretime-playout[34781]: fetch_queue: ThreadQueue[Dict[str, Any]],
Dec 2 10:57:37 serverXY libretime-playout[34781]: TypeError: ‘type’ object is not subscriptable
Dec 2 10:57:37 serverXY systemd[1]: libretime-playout.service: Main process exited, code=exited, status=1/FAILURE
Dec 2 10:57:37 serverXY systemd[1]: libretime-playout.service: Failed with result ‘exit-code’.
Dec 2 10:57:37 serverXY systemd[1]: libretime-playout.service: Scheduled restart job, restart counter is at 2.
Dec 2 10:57:37 serverXY systemd[1]: Stopped LibreTime Playout Service.
Dec 2 10:57:37 serverXY systemd[1]: Started LibreTime Playout Service.