Message Oracle ORA-39165 - Schema string was not found.

ERRORSchema string was not found.
CAUSEIf exporting or importing over the network, either the user specified a schema name that was not found in the source database or else the user lacked the proper EXP_FULL_DATABASE or IMP_FULL_DATABASE role that would allow them to access another schema. For importing from files, the user specified a schema name not found in the dump file set.
ACTIONRetry the operation using the correct schema name.