DB BR 363 services in journey mode in which you have to arrange passenger cars are broken and can not even be started. So after you start this services objective marker is not visible and never shows up.
Maybe you recognised yourself but I actually report only if certain that something has to be reported.
There are other threads in this section of the forums. There is a workaround. You go on foot to the yard, enter the engine a few minutes before start time and you can play the services. It still is a bug, but at leats you can do something and enjoy the services.
Just for the record, I've successfully driven and enjoyed all of the BR363 services that involve assembling passenger trains on my PC. They start and run without problems in service mode. I can't comment about journey mode, since I never use it. Your OP implies that the problem you have experienced happens to everyone on all platforms -- which simply is not true.
Great, I used the search function instead of opening a new thread Just wanted to bump this, still not resolved (PC) ... The Error with passenger coach journey mission 1: Go to 1st location - you arrive there, no next marker spawns and can't be seen on "the map", too. Didn't bother to try the next mission yet since I tried the first one like 4 times