IT Services (SLA) is not working properly

[cloudmafia]

Hi,

I have recently configured zabbix IT services but its not working and show false SLA, there seems like some issue with zabbix or might with configuration, I have configured zabbix with Zabbix agent unreachable trigger on hosts and after adding new SLA it works well for sometime but then again it start showing incorrect SLA, there is my typical configuration -

I have created Hierarchy - Under root i have created an SLA with following -

Name - GROUP_ABC
Parent service - root
Status calculation algorithm - Problem if, atleast one child has problem.
Calculate SLA, acceptable SLA (in %)  - 99.95
Trigger - none

and then i have added Hosts -

Name - SERVER_ABC012
Parent service - GROUP_ABC
Status calculation algorithm - Problem if, atleast one child has problem.
Calculate SLA, acceptable SLA (in %)  - 99.95
Trigger - SERVER_ABC012:Zabbix agent on SERVER_ABC012 is unreachable for 5 minutes

root
  [-] GROUP_ABC
       ....SERVER_ABC012
       ....SERVER_ABC013

when i check SLA by "Monitoring" and "IT Services" and clicking on added SLAs (hosts triggers) is showing hosts in unreachable since 2-3days but there are no issues in hosts...

I don't know whats wrong, please help...also find the attachments.