Unable Start Zabbix-Server

[Admin-SIS-56]

Help,

my zabbix server does not start,
i have this error

12763:20191011:145312.290 server #50 started [unreachable poller #8]
12764:20191011:145312.294 server #51 started [unreachable poller #9]
zabbix_server [12679]: failed to fork: [12] Cannot allocate memory
zabbix_server [12679]: failed to fork: [12] Cannot allocate memory
..
..
12745:20191011:145312.482 [Z3001] connection to database 'zabbix' failed: [0] FATAL: out of memory


i don't understand why
because I have more than 9Gb Free memory

******@vm-zabbix-srv:/var/log/zabbix# free -h
total utilisé libre partagé tamp/cache disponible
Mem: 9,8G 221M 9,1G 70M 425M 9,2G
Partition d'échange: 975M 0B 975M
*********@vm-zabbix-srv:/var/log/zabbix#

My Configuration File :
ListenPort=10051
LogFile=/var/log/zabbix/zabbix_server.log
LogFileSize=20
DebugLevel=3
PidFile=/var/run/zabbix/zabbix_server.pid
SocketDir=/var/run/zabbix
DBHost=localhost
DBUser=****************
DBPassword=**************

StartPollers=20
StartPreprocessors=3
StartPollersUnreachable=10
StartTrappers=5
StartPingers=8
StartDiscoverers=3
StartHTTPPollers=3
StartVMwareCollectors=5
VMwareFrequency=60
VMwareCacheSize=64M
SNMPTrapperFile=/var/log/snmptrap/snmptrap.log
HousekeepingFrequency=5
MaxHousekeeperDelete=5000
CacheSize=2048M
HistoryCacheSize=256M
HistoryIndexCacheSize=32M
TrendCacheSize=16M
ValueCacheSize=128M
Timeout=30

Server :
Virtual Machine On VmWare 6.5
4 Vcpu
10 Go Ram
OS Ubuntu 18.04
PostgreSQL 10.10

Christophe.

[Admin-SIS-56]

Hi,
I answer myself,
my problem came from limitations on postgresql processes

vi /etc/security/limits.conf

Ch.