SSO authentication error for service account

Hi All,

     Recently we did made change in SSO for source identity because the SSO was still trying to authenticate old DC ( Server got decommissioned), but after that changes it seems

service account for monitoring fails to login to vCenter server. ( see screen shot.) When i checked the vpxd logs its shows error

2015-10-18T05:10:13.246+02:00 [06776 info '[SSO]' opID=f39cceaf] [UserDirectorySso] Authenticate(us\PMonitor22, "not shown")

Any help much appreciated.

Thanks

vm2014