在主库上通过dgmgrl去切换到备库的时候报错：DGMGRL> connect sys/3EEcAjsGcWdr@orcl
Connected.
DGMGRL> switchover to stdorcl
Performing switchover NOW, please wait…
Operation requires a connection to instance “stdorcl” on database “stdorcl”
Connecting to instance “stdorcl”…
Unable to connect to database
ORA-12514: TNS:listener does not currently know of service requested in connect descriptor

Failed.
Warning: You are no longer connected to ORACLE.

    connect to instance "stdorcl" of database "stdorcl"

备库的参数：
StaticConnectIdentifier = ‘(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=std)(PORT=13899))(CONNECT_DATA=(SERVICE_NAME=stdorcl)(INSTANCE_NAME=stdorcl)(SERVER=DEDICATED)))’
但是，主库是可以通过tnsping通stdorcl的
[oracle@pri admin]$ tnsping stdorcl

TNS Ping Utility for Linux: Version 11.2.0.4.0 - Production on 08-APR-2020 18:47:25

Copyright © 1997, 2013, Oracle. All rights reserved.

Used parameter files:

Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = std)(PORT = 13899)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = stdorcl)))
OK (0 msec)

备库的监听状态如下：
Listening Endpoints Summary…
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=std)(PORT=13899)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC13899)))
Services Summary…
Service “stdorcl” has 1 instance(s).
Instance “stdorcl”, status UNKNOWN, has 1 handler(s) for this service…
Service “stdorcl_DGMGRL” has 1 instance(s).
Instance “stdorcl”, status UNKNOWN, has 1 handler(s) for this service…
The command completed successfully

备库重启监听多次，还是有这个问题。抓狂啊。。。
请问各位，这个问题大概的原因是什么？