VNX Unified: Failed to manage SP due to excessive failed authentication attempts (User Correctable)

1. Failed to manage SP from ControlStation:
[nasadmin@CS0~]$ /nas/sbin/navicli -h spa getagent
Error returned from the Management Server on xx.xx.xx.xx
Authentication failed. Possible reason for failure is excessive failed authentication attempts.

2. Restarted the management server on SP but did not resolve the problem.

3. Updated the correct SP credential on ControlStation but did not work.

There was a wrong credential configured on another host which was trying to access the SP. Error messages on SP is as below:
***************
B 11/17/16 15:29:34 4640 Access is denied called by 'srmuser'. Application Accessed: ManagementServer. Result: Failure.
B 11/17/16 15:29:34 4640 Access is denied called by 'srmuser'. Application Accessed: ManagementServer. Result: Failure.
B 11/17/16 15:29:34 4640 Access is denied called by 'srmuser'. Application Accessed: ManagementServer. Result: Failure.

SP blocked access from all hosts because of the the excessive requests from this host.

Find out the problematic host which configured the wrong credential, and correct it. The Username and IP address can be found from SP log.