Frequest False alert's on Zabbix agent not reachable.

We get frequent false alert on Zabbix agent not reachable with the expression
Trigger Expression:

=1

When manually checked using zabbix_get the agent is reachable and no issues.

[[email protected] ~]# /usr/local/zabbix/bin/zabbix_get -s CLIENT-k agent.ping
1
[[email protected] ~]#

Please advise.