Zabbix Server is not working: the information dispaly may not be current

 Details Cannot display item queue.

• Connection to Zabbix server "localhost:10051" refused. Possible reasons: 1. Incorrect "NodeAddress" or "ListenPort" in the "zabbix_server.conf" or server IP/DNS override in the "zabbix.conf.php"; 2. Security environment (for example, SELinux) is blocking the connection; 3. Zabbix server daemon not running; 4. Firewall is blocking TCP connection. Connection refused

Observation:- In Centos 9

[root@nmtool ~]# systemctl status zabbix-server.service

● zabbix-server.service - Zabbix Server

     Loaded: loaded (/usr/lib/systemd/system/zabbix-server.service; enabled; vendor preset: d>     Active: activating (auto-restart) (Result: exit-code) since Fri 2023-02-03 10:36:52 IST;>    Process: 57289 ExecStart=/usr/sbin/zabbix_server -c $CONFFILE (code=exited, status=0/SUCC>    Process: 57295 ExecStop=/bin/kill -SIGTERM $MAINPID (code=exited, status=1/FAILURE)

   Main PID: 57291 (code=exited, status=0/SUCCESS)

        CPU: 404ms

[root@nmtool ~]# tail -f /var/log/zabbix/zabbix_server.log

configuration syncer [syncing configuration](main+0x388) [0x55cb66f8e37e]

 60575:20230203:115209.991 2: /lib64/libc.so.6(+0x3feb0) [0x7f1fbc63feb0]

 60575:20230203:115209.991 1: /lib64/libc.so.6(__libc_start_main+0x80) [0x7f1fbc63ff60]

 60575:20230203:115209.991 0: /usr/sbin/zabbix_server: configuration syncer [syncing configuration](_start+0x25) [0x55cb66f8ce45]

 60575:20230203:115209.991 [file:dbconfig.c,line:97] __zbx_shmem_malloc(): out of memory (requested 32 bytes)

 60575:20230203:115209.991 [file:dbconfig.c,line:97] __zbx_shmem_malloc(): please increase CacheSize configuration parameter

 60572:20230203:115209.996 One child process died (PID:60575,exitcode/signal:1). Exiting ...

 60573:20230203:115209.996 HA manager has been paused

 60573:20230203:115210.001 HA manager has been stopped

 60572:20230203:115210.003 Zabbix Server stopped. Zabbix 6.2.4 (revision 885eaefa6f7).

[root@nmtool ~]#  cd /etc/zabbix/

[root@nmtool zabbix]# pwd

/etc/zabbix

[root@nmtool zabbix]# vim zabbix_server.conf

I modified the value in the configuration file and save it and restart the zabbix server.
VMwareCacheSize=2048M
CacheSize=6144M
HistoryCacheSize=1024M
TrendCacheSize=1024M
HistoryTextCacheSize=1024M
ValueCacheSize=4096M

My Problem was resolved.

 My Issue was with out of Memory. 

Find out your problem in log file and troubleshoot it.

 Thank You