Enable SCOM to monitor network devices(Access Points) using hostname as well.
During discovery using hostname , SCOM works. But since the network device is using DHCP ( in most cases ,the APs) , it will keep changing if it is been rebooted. Once the AP got new IPs, SCOM will no longer monitor it as SCOM is monitoring it via IP .Even if the discovery is made recurring , SCOM will create a new record with different IP but same hostname. Thus the AP is "greyed" out. The only way now is to delete the existing record and manually rediscover.