Error ORA-12528: all appropriate instances are blocking new connections

Products

• Data Loss Prevention Enforce
• Data Loss Prevention Oracle Standard Edition 2

Issue/Introduction

Users are unable to login to the Enforce console and the localhost_access log records an HTTP 500 status code.

In the course of troubleshooting this error, when attempting to log into SQL*Plus as a user other than sys, the following error appears:

ORA-12528 TNS:listener: all appropriate instances are blocking new connections

The same error message is also captured in the localhost log:

File: Enforce\logs\tomcat\localhost.2025-01-27.log
Date: 1/27/2025 8:35:24 AM
Thread: 18
Level: WARNING
Source: com.vontu.util.jdbc.JDBCTestConnection
Message: Cannot connect to database
Cause:
java.sql.SQLException: Unable to start the Universal Connection Pool: oracle.ucp.UniversalConnectionPoolException: Cannot get Connection from Datasource: java.sql.SQLException: Listener refused the connection with the following error:
ORA-12528, TNS:listener: all appropriate instances are blocking new connections

Resolution

This condition may be temporary, such as at instance startup. To identify the current state of the database, follow this procedure:

1. On the server hosting the Oracle service and the Protect database, open a command prompt run as administrator
2. Enter the command SQLPlus
3. Enter the following for the user-name: sys AS sysdba
4. Enter the password for the sys account
5. Execute the following statement:

   SELECT * FROM v$instance;

   If successful, the script output should look similar to the following:

   INSTANCE_NUMBER INSTANCE_NAME
   --------------- ----------------
   HOST_NAME
   ----------------------------------------------------------------
   VERSION           STARTUP_T STATUS       PAR    THREAD# ARCHIVE LOG_SWITCH_WAIT
   ----------------- --------- ------------ --- ---------- ------- ---------------
   LOGINS     SHU DATABASE_STATUS   INSTANCE_ROLE      ACTIVE_ST BLO
   ---------- --- ----------------- ------------------ --------- ---
                 1 protect
   L-018591-A
   10.2.0.4.0        07-DEC-09 OPEN         NO           1 STOPPED
   ALLOWED    NO  ACTIVE            PRIMARY_INSTANCE   NORMAL    NO

   Note that the DATABASE_STATUS is ACTIVE. If the database isn't open, this is the cause of the error
   
   
6. If the database status is not active, enter the command STARTUP in SQL*Plus