Following tasks could not be completely planned - by: #Chris

Hello all,

I have a problem if I assign ressources to Meetings. If I run the planning I always get the follwing pop-up Following tasks could not be completely planned
See also the attached pic.
If I do this with an activity on the same ressources it is no problem and the planning runs fine. Also on the same day there is no other activity, etc for that ressources
So I do not know what I am missing.

Any help is very much appreciated