repmgr won't update witness after failover

Hey,
I have set up three nodes of postgresql 9.4 with repmgr in this way:
1. master - node1
2. standby - node2
3. witness - node3

Now I have set up the replication and the witness as it says here:
https://github.com/2ndQuadrant/repmgr/blob/master/FAILOVER.rst

Now when I do 'kill -9 $(pidof postmaster)' The witness detects that
something went wrong and fails over from node1 to node2
But when I setup the replication now to work from node2 to node1 and I kill
the postgresql process it doesn't failover and the repmgrd log shows the
following message:
unable to determine a valid master server; waiting 10 seconds to retry...

it seems that the witness doesn't know about the new standby server..

Has anyone got any idea about what am I doing wrong here?

Best regards,
Aviel Buskila