After a simulation run, I get warnings that some paths could not be found. Does it mean that during the simulation not all vehicles were placed in the network?

If you receive the following message:
'No path from parking lot <PARKING LOT NO> to parking lot <PARKING LOT NO> can be used because of the following connector closures: <LINK NO>, for the following vehicle types: <VEHICLE TYPE NO>', it is just a warning.
It does not mean that vehicles are not placed into the network unless there is another message that states:
'No parking lot found from zone <ZONE NO> with at least one path to destination zone <ZONE NO>. Vehicles of type <VEHICLE TYPE NO> from the matrix <MATRIX NO> could not be placed in the network.'