Multi-Vehicle Simulation with Gazebo Could not find a connection between 'local_origin_ned' and 'fcu'

Hi,

I am trying to run simulations according to the tutorial presented here:
https://dev.px4.io/v1.9.0/en/simulation/multi-vehicle-simulation.html

Unfortunately, after starting and the appearance of the simulation, such errors like this begin to appear:
[ERROR] [1568828840.383078461, 74.200000000]: ODOM: Ex: Could not find a connection between ‘local_origin_ned’ and ‘fcu’ because they are not part of the same tree.Tf has two or more unconnected trees.
[ERROR] [1568828840.497022020, 74.236000000]: ODOM: Ex: Could not find a connection between ‘local_origin_ned’ and ‘fcu’ because they are not part of the same tree.Tf has two or more unconnected trees.
[ERROR] [1568828843.170535125, 75.200000000]: ODOM: Ex: Could not find a connection between ‘local_origin_ned’ and ‘fcu’ because they are not part of the same tree.Tf has two or more unconnected trees.
[ERROR] [1568828843.176395245, 75.200000000]: ODOM: Ex: Could not find a connection between ‘local_origin_ned’ and ‘fcu’ because they are not part of the same tree.Tf has two or more unconnected trees.
[ERROR] [1568828843.253139167, 75.236000000]: ODOM: Ex: Could not find a connection between ‘local_origin_ned’ and ‘fcu’ because they are not part of the same tree.Tf has two or more unconnected trees.

Do somebody know how repair it or know other method to set simulation in gazebo with three iris drone?

I am using Ubuntu 18.04.03 as VM in VirtualBox.