1. Update Zabbix server to 6.0.15
2. After 15 minutes check graph of server with template Linux by Zabbix agent - it`s empty CPU Jumps and Network traffic
No errors on zabbix-agent and Zabbix-server!!

Log from update:

Start-Date: 2023-04-01  16:05:32
Commandline: apt-get dist-upgrade
Upgrade: zabbix-java-gateway:amd64 (1:6.0.14-1+debian11, 1:6.0.15-1+debian11), zabbix-server-mysql:amd64 (1:6.0.14-1+debian11, 1:6.0.15-1+debian11), zabbix-agent:amd64 (1:6.0.14-1+debian11, 1:6.0.15-1+debian11), zabbix-get:amd64 (1:6.0.14-1+debian11, 1:6.0.15-1+debian11), zabbix-frontend-php:amd64 (1:6.0.14-1+debian11, 1:6.0.15-1+debian11)
End-Date: 2023-04-01  16:05:37

Like You see exacly after upgrade he stop working:

I check and this is not Zabbix-agent problem because on other server i still got 6.0.14 version and graph stop working too - so this is issue with Zabbix-Server.

Best Regards
TaKeN