ORA-11403
Data Guard site data invalid or incomplete
Cause
The SYS.DATA_GUARD_SITE$ row contained incorrect or incomplete details used to form a connection to the site. The previous error on the error stack should give more insight into what is incorrect or incomplete. For example, an ORA-27476 indicates the defined or defaulted credential could not be accessed.
Action
If it is not obvious from the context of the error which site site entry is causing the problem or which piece of data from the entry is incorrect or incomplete then more details can be found in the trace file of the process that originally reported the error. Data Guard Broker is the preferred method to maintain the site configuration data. Try removing and adding the site again.