I just started the service [ on the Dresden-Riesa route, after 5 second i get the notification about a SPAD. So this service is not playable
Try spawning on foot at the right place and time (ex since it starts at 16:45, you must spawn at 16:40).
Same issue on some freight services on Kinzigtalbahn, as said before spawning on foot at the departure Place few minutes before Is the workaround
Ditto. There are services that can be only completed this way. I remember back when I was on TSW2 on the Canada route set to journey mode for a certain service and my train had a red light when it should of not been, only after I spawned on foot I got the green light. If journey/guided experience does not work or gives you a red light when it should not, frist try service/time table. If that does not work, then spawn on foot.