Reason 1: Service is not running.
Solution: The Oracle server is down or the Oracle server is not accessible from the Applications Manager machine.
Try to open a socket to the Oracle machine by executing the following command from the machine in which Applications Manager server is running:
telnet oracle_hostname oracle_portnumber.
Reason 2: Unable to connect to Oracle Server.
Connection refused (DESCRIPTION=(TMP=)(VSNNUM=135294976)(ERR=12505)(ERROR_STACK=(ERROR =(CODE=12505)(EMFI=4))))
Solution: The Instance Name (Service Name) specified in Applications Manager is wrong or this instance is not running. Try to connect to Oracle using SQLPlus and "Connect String/Service Name" should be given as Instance Name in Applications Manager when you are connecting through the SQLPlus.
The instance name can also be found out from the <oracle-installation directory\network\admin\listener.ora>. In <listener.ora> file, you will have an entry <SID_NAME = orcl>, where orcl is the Instance name.
The instance name can also be found out from the<oracle-installation directory\network\admin\tnsnames.ora>. In <tnsnames.ora> file, you will have an entry <SERVICE_NAME = orcl>, where orcl is the Instance name.
Reason 3: Unable to connect to Oracle Server. Error Message: 7
Solution: Download the latest Oracle 11g database JDBC driver (ojdbc6.jar file), rename it as classes12.zip and copy it to <AppManager_Home>\working\classes directory. Then restart Applications manager and try to add Oracle DB server again.
Reason 4: The user does not have proper privileges. Enter a user with DBA privileges.
Solution: A user with CONNECT and SELECT_CATALOG_ROLE roles is required for monitoring by Applications Manager. So configure a user with these permissions and try with that user in Applications Manager.
Reason 5: ORA-28040: No matching authentication protocol
Solution 1: In the Oracle DB server installation directory, edit the sqlnet.ora file (present under <oracle home>\network\admin directory) and remove the entry SQLNET.ALLOWED_LOGON_VERSION=10 in that file or set to lower version. Then restart Oracle DB server and try to add it in Applications Manager.
Reason 6: Io exception: Got minus one from a read call
Solution 1: Make sure you are connecting to the correct port, a wrong port can also give the error above. Also, check the SID used to connect in tnsnames.ora and Listener.ora are correct.
Solution 2: It seems you have enabled ACL on the listener. You can follow these steps to avoid the error:
a. Modify $ORACLE_HOME/network/admin/sqlnet.ora file with following parameter:
tcp.validnode_checking = no
b. If you don't want to disable this, you can put the machine names (provide Applications Manager hostname) as follows and restart the listener:
Solution 3: Check the number of processes and shared pool size.
Show parameter SHARED_POOL_SIZE;
Show parameter Processes;
If the values are insufficient, increase the size using:
Alter system set SHARED_POOL_SIZE=<size the environment demands>M;
Alter system set PROCESSES=<Size the environment demands> SCOPE=SPFILE;
Note: If none of the above fixes the problem, execute the file OracleDebug.bat under <AppManager_Home>\bin\troubleshooting and send the result.