NetWorker：Oracleバックアップがエラー「ORA 03113 通信チャネル上のファイルの終わり」で失敗する

エラー メッセージは次のように表示されます。

RMAN> run {
2> allocate channel c1 type 'sbt_tape' format '%d_%U';
3> }

using target database control file instead of recovery catalog
PSDRPC returns significant error 3113.
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of allocate command on c1 channel at 10/27/2023 13:07:49
ORA-03113: end-of-file on communication channel

sbttest was also failed:
[GW-DB:oracle:SJGW80:/]$sbttest /etc/hosts -no_proxy_backup -no_proxy_restore
The sbt function pointers are loaded from libobk.so library.
(pid 3839660): Failed to resolve hostname client1 to an internet address. Please verify a mapping for client1 exists in the /etc/hosts file or DNS.
-- sbtinit succeeded
(pid 3839661): Failed to resolve hostname client1 to an internet address. Please verify a mapping for client1 exists in the /etc/hosts file or DNS.
-- sbtinit (2nd time) succeeded
sbtinit: Media manager supports SBT API version 2.0
sbtinit: vendor description string=NMDA Oracle v19.4.0.6
sbtinit: allocated sbt context area of 2280 bytes
sbtinit: Media manager is version 19.4.0.0
sbtinit: proxy copy is supported
sbtinit: maximum concurrent proxy copy files is 0
(pid 3839659): Failed to resolve hostname client1 to an internet address. Please verify a mapping for client1 exists in the /etc/hosts file or DNS.

[client1:root:/]# ls -arlt /etc/hosts
-rw------- l root root 233 10 20 11:27 /etc/hosts

[client1:oracle:/]$cat /etc/hosts
cat: /etc/hosts: Permmission denied