Problem restarting Zabbix proxies

[slinuxadm]

Hello everyone,
We are running zabbix_server (Zabbix) 6.2.6 with 4 proxies (zabbix_proxy (Zabbix) 6.2.6) on Red Hat Enterprise Linux 8.7 (Ootpa).

I attempted to restart the proxies with systemctl restart zabbix-proxy and systemctl status zabbix-proxy now shows:
zabbix-proxy.service - Zabbix Proxy
Loaded: loaded (/usr/lib/systemd/system/zabbix-proxy.service; enabled; vendor preset: disabled)
Active: deactivating (stop-sigterm) (Result: exit-code) since Thu 2023-02-16 08:36:15 CET; 48min ago
Process: 1961 ExecStart=/usr/sbin/zabbix_proxy -c $CONFFILE (code=exited, status=0/SUCCESS)
Main PID: 1963 (code=exited, status=1/FAILURE)
Tasks: 1141 (limit: 823018)

The only entries in /var/log/zabbix/zabbix_proxy.log, prior to and since attempting the restart and other than those similar to:
1986:20230216:091858.700 received configuration data from server at "xx.xxx.xx.xx", datalen 19160595
are:
2003:20230216:083615.030 executing housekeeper
2003:20230216:083617.865 housekeeper [deleted 736654 records in 2.828684 sec, idle for 1 hour(s)]

ps -aef | egrep '[1]963' shows:
zabbix 2373 1 0 08:36 ? 00:00:02 /usr/sbin/zabbix_proxy: poller Services [got 3 values in 1.021963 sec, getting values]

ps -aef | egrep '[1]961' shows nothing

This problem exists on all four proxies.

Any help is appreciated.

Thanks!

[slinuxadm]

UPDATE
Starting the zabbix proxy with systemctl start zabbix-proxy does not create the PID file in /run/zabbix as expected, according to: /usr/lib/systemd/system/zabbix-proxy.service

[Unit]
Description=Zabbix Proxy
After=syslog.target
After=network.target
After=mysql.service
After=mysqld.service
After=mariadb.service
After=postgresql.service
After=pgbouncer.service
After=postgresql-9.4.service
After=postgresql-9.5.service
After=postgresql-9.6.service
After=postgresql-10.service
After=postgresql-11.service
After=postgresql-12.service
After=postgresql-13.service
After=postgresql-14.service

[Service]
Environment="CONFFILE=/etc/zabbix/zabbix_proxy.conf"
EnvironmentFile=-/etc/sysconfig/zabbix-proxy
Type=forking
Restart=on-failure
PIDFile=/run/zabbix/zabbix_proxy.pid
KillMode=control-group
ExecStart=/usr/sbin/zabbix_proxy -c $CONFFILE
ExecStop=/bin/kill -SIGTERM $MAINPID
RestartSec=10s
TimeoutSec=0

[Install]
WantedBy=multi-user.target

Contents of /run/zabbix
total 4.0K
-rw-rw-r-- 1 zabbix zabbix 4 Feb 16 13:17 zabbix_agentd.pid
srwx------ 1 zabbix zabbix 0 Feb 16 13:17 zabbix_proxy_rtc.sock
srwx------ 1 zabbix zabbix 0 Feb 16 13:18 zabbix_proxy_preprocessing.sock
srwx------ 1 zabbix zabbix 0 Feb 16 13:18 zabbix_proxy_availability.sock