CALL_FUNCTION_REMOTE_ERROR - Password logon no longer possible

Hi ,

    I checked my system dumps ST22 and i realized from many days , there is runtime error every 2-3 hrs  called CALL_FUNCTION_REMOTE_ERROR.  Short Text -  "Password logon no longer possible - too many failed attempts"  SAPSYS

What i understood is that this error means probably a RFC which in background while running encounters a logon problem. Although i checked in SU01 there is no user with SAPSYS.

Kindly let me know how can i solve this problem and what is the cause of the same.

I am attaching the screenshots of the dump.

Regards

Amber