I found that if I add this section with capabilities :
[privsep_namespace] capabilities = CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH, CAP_SYS_PTRAC
in my /etc/neutron/neutron.conf file the error is gone
I found that if I add this section with capabilities :
[privsep_namespace] READ_SEARCH, CAP_SYS_PTRAC
capabilities = CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_DAC_OVERRIDE, CAP_DAC_
in my /etc/neutron/ neutron. conf file the error is gone