I installed on machine 2 the next packages and not what I mentioned on my last comment :
---> Package postgresql96.x86_64 0:9.6.10-1PGDG.rhel6 will be installed
---> Package postgresql96-contrib.x86_64 0:9.6.10-1PGDG.rhel6 will be installed
---> Package postgresql96-libs.x86_64 0:9.6.10-1PGDG.rhel6 will be installed
---> Package postgresql96-server.x86_64 0:9.6.10-1PGDG.rhel6 will be installed