[root@zabbix zabbix]# cat /var/log/zabbix/zabbix_server.log | grep srv1.mydomain.lan
1834:20210316:165431.668 cannot send list of active checks to "192.168.xx.xxx": host [srv1.mydomain.lan] not found
1829:20210316:165656.089 enabling Zabbix agent checks on host "srv1.mydomain.lan": host became available
1818:20210316:172738.656 item "srv1.mydomain.lan:vfs.dev.read.await[sda]" became not supported: Cannot evaluate expression: "Cannot evaluate function "last()": not enough data.".
1820:20210316:172739.658 item "srv1.mydomain.lan:vfs.dev.write.await[sda]" became not supported: Cannot evaluate expression: "Cannot evaluate function "last()": not enough data.".
1822:20210316:173738.223 item "srv1.mydomain.lan:vfs.dev.read.await[sda]" became supported
1817:20210316:173739.223 item "srv1.mydomain.lan:vfs.dev.write.await[sda]" became supported
1861:20210318:170903.928 Zabbix agent item "vfs.fs.size[/,used]" on host "srv1.mydomain.lan" failed: first network error, wait for 15 seconds
1869:20210318:170923.614 Zabbix agent item "vfs.fs.size[/,total]" on host "srv1.mydomain.lan" failed: another network error, wait for 15 seconds
1869:20210318:170938.815 Zabbix agent item "vfs.fs.size[/,pused]" on host "srv1.mydomain.lan" failed: another network error, wait for 15 seconds
1869:20210318:170954.083 temporarily disabling Zabbix agent checks on host "srv1.mydomain.lan": host unavailable