Unable to attach ISO Domain onto a specific Host in RHEV-M 3.2 and seeing 'err=['Password: /bin/su: incorrect password']" in /var/log/messages

Issue

We can not attach ISO Domain onto a specific Host in RHEV-M.
When we try to do it, following errors occurred on RHEV-M and in syslog each

• Error message on RHEV-M

Error while executing action Attach Storage Domain: Could not obtain lock

• Error messages in syslog on a specific Host

Dec 16 20:07:01 LCNDCTLHA63 vdsm TaskManager.Task ERROR Task=`f783f209-9e33-4cfd-951c-0f7c6e2ca143`::Unexpected error#012Traceback (most recent call last):#012  File "/usr/share/vdsm/storage/task.py", line 857, in _run#012    return fn(*args, **kargs)#012  File "/usr/share/vdsm/logUtils.py", line 41, in wrapper#012    res = f(*args, **kwargs)#012  File "/usr/share/vdsm/storage/hsm.py", line 1098, in attachStorageDomain#012    pool.attachSD(sdUUID)#012  File "/usr/share/vdsm/storage/securable.py", line 68, in wrapper#012    return f(self, *args, **kwargs)#012  File "/usr/share/vdsm/storage/sp.py", line 935, in attachSD#012    dom.acquireClusterLock(self.id)#012  File "/usr/share/vdsm/storage/sd.py", line 474, in acquireClusterLock#012    self._clusterLock.acquire(hostID)#012  File "/usr/share/vdsm/storage/clusterlock.py", line 111, in acquire#012    raise se.AcquireLockFailure(self._sdUUID, rc, out, err)#012AcquireLockFailure: Cannot obtain lock: "id=659f450d-86db-4427-a5a6-02bb60e93a88, rc=125, out=[], err=['Password: /bin/su: incorrect password']"

We had changed a Host's password. after that, these errors occurred. so, re-changed it again as original ones. but it still occurs.