The connection pool named: |apex|rt| is not correctly configured, due to the following error(s): ORA-28000: The account is locked.

The connection pool named: |apex|rt| is not correctly configured, due to the following error(s): ORA-28000: The account is locked.

Check if there is any Locked User :

CONN SYS/SYS@ORCLPDB AS SYSDBA

select username, account_status, profile        from dba_users 
    where username in ('APEX_PUBLIC_USER','APEX_LISTENER','APEX_REST_PUBLIC_USER');  

Run the following  :

ALTER USER APEX_PUBLIC_USER IDENTIFIED BY Apex123 ACCOUNT UNLOCK;
ALTER USER APEX_LISTENER IDENTIFIED BY Apex123 ACCOUNT UNLOCK;
ALTER USER APEX_REST_PUBLIC_USER identified BY Apex123 ACCOUNT UNLOCK;

ALTER USER APEX_200100 IDENTIFIED BY Apex123 ACCOUNT UNLOCK;
ALTER USER APEX_INSTANCE_ADMIN_USER IDENTIFIED BY Apex123 ACCOUNT UNLOCK; 

Windows :

Go to :  D:\ords\conf\ords\conf
Give Password at each xml file like : !Apex123 [Must add an ! exclamatory sign. before password. ]

Files are :

apex.xml
apex_al.xml
apex_pu.xml
apex_rt.xml

apex.xml :

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
<properties>
<comment>Saved on Wed Jun 02 22:29:52 BDT 2021</comment>
<entry key="db.password">!Apex123</entry>
<entry key="db.username">APEX_PUBLIC_USER</entry>
</properties>

apex_al.xml :

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">

<properties>

<comment>Saved on Wed Jun 02 23:12:48 BDT 2021</comment>

<entry key="db.password">!Apex123</entry>

<entry key="db.username">APEX_LISTENER</entry>

</properties>

apex_pu.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">

<properties>

<comment>Saved on Wed Jun 02 23:12:48 BDT 2021</comment>

<entry key="db.password">!Apex123</entry>

<entry key="db.username">ORDS_PUBLIC_USER</entry>

</properties>

apex_rt.xml :

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">

<properties>

<comment>Saved on Wed Jun 02 23:12:48 BDT 2021</comment>

<entry key="db.password">!Apex123</entry>

<entry key="db.username">APEX_REST_PUBLIC_USER</entry>

</properties>

Now Uninstall ORDS with the following command :

D:

CD ORDS

"C:\Program Files\Java\jdk-15.0.1\bin\java" -jar ords.war uninstall

Now Install ORDS with following command :

"C:\Program Files\Java\jdk-15.0.1\bin\java" -jar ords.war install advanced

copy ords.war from 

D:\ords  

and paste to 

C:\Program Files\Apache Software Foundation\Tomcat 9.0\webapps

Now Restart Services :

Now Restart Tomcat.

Now run Apex with ORDS :

localhost:8080/ords
or
127.0.0.1:8080/ords