to solve this problem follow the following steps:
1.Stop the nmlsdh process manually.
2.Modify bDisplayServerTrailAlarm from 0 to 1 in U2000server\nml\nmlsdh\conf\cfg\nmlsdh.cfg
3.Restart the nmlsdh process.
4.Browse current alarms about the faulty trail again.Alarms are relocated and relationship between the trail and its alarms will be updated. As a result, alarm status is synchronized.