本地登录无异常，创建测试用户，电脑Plsql登录提示报错ORA-28040，处理后再次登录提示密码错误，最后重置密码再次登录OK？
通过这个问题再次测试及反思：
1.ORA-28040
[oracle@d2:/u03/app/oracle/product/19.0.0/db_1/network/admin]$ sqlplus cc/cc@192.168.60.45:1521/pp1
SQL*Plus: Release 19.0.0.0.0 - Production on Fri Jul 24 22:32:19 2020
Version 19.5.1.0.0
Copyright (c) 1982, 2019, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.5.1.0.0
SQL>
[oracle@d2:/u03/app/oracle/product/19.0.0/db_1/network/admin]$ oerr ora 28040
28040, 0000, "No matching authentication protocol"
// *Cause: There was no acceptable authentication protocol for
//
either client or server.
// *Action: The administrator should set the values of the
//
SQLNET.ALLOWED_LOGON_VERSION_SERVER and
//
SQLNET.ALLOWED_LOGON_VERSION_CLIENT parameters, on both the
//
client and on the server, to values that match the minimum
//
version software supported in the system.
//
This error is also raised when the client is authenticating to
//
a user account which was created without a verifier suitable for
//
the client software version. In this situation, that account's
//
password must be reset, in order for the required verifier to
//
be generated and allow authentication to proceed successfully.
$ cd $ORACLE_HOME/
$ cd network/admin/
$ vi sqlnet.ora
SQLNET.ALLOWED_LOGON_VERSION_SERVER=10
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=10
SQLNET.ALLOWED_LOGON_VERSION=8
添加SQLNET参数即可，允许客户端向下兼容。