Zabbix was down

[mr.cocco]

I create this trigger:
({mach1:icmpping.last(0)}=0)|({mach2:icmpping.last (0)}=0)|({mach3:icmpping.last(0)}=0)

mach2 status is OK
({mach2:icmpping.last(0)}=0)

mach3 status is OK
({mach3:icmpping.last(0)}=0)

mach1 is the pc where zabbix is installed ({mach1:icmpping.last(0)}=0)|({mach2:icmpping.last (0)}=0)|({mach3:icmpping.last(0)}=0)
error: ZABBIX was down

but if I create the trigger ({mach1:icmpping.last(0)}=0) the status of this triggers is OK

can anyone help me!