ORA-28029: could not authorize remote server for user string
Cause: During the course of opening a privileged database link, the remote server was found to lack the necessary authorizations to connect as the current global user. This may be because the server was not authorized by the network security service. Or it may be because the local server is restricting access by the remote server using the DBMS_SECURITY_DOMAINS_ADMIN package
Action: Grant the remote server the proper authorization to connect as the given global user, and check that the local server is not restricting access
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