Getting continous event on vCenter

Hi,

We had implemented vSphere 5.1 in our environment along with heartbeat and vCOPS.

Now the issue is we are getting continuous events in our vCenter server as 'Cannot login username @127.0.0.1'.

I tried disabling the plugins but still the events were getting generated. Also there are not any monitoring tools on ESXi.

Any suggestions to resolve this issue are appreciated.

Thanks,

Sanat