The default time for OK and status change trigger is 30 minutes which means the OK keeps blinking on the screen for that long.
There are two ways to change this:
Go to Administration > General > Trigger displaying options (drop down on right)
Change values of following as desired
- Display OK triggers for
- On status change triggers blink for
The other way is to directly change it in DB (MySQL in this case):
mysql -u zabbix -p <PASSWORD> -e 'UPDATE config SET `ok_period`=60, `blink_period`=60' zabbixserverdb
This is more helpful for automation.