EM cannot connect to database instance Solution

Symptom: the Database is open or can be connected to the Database from sqlplus. When you connect to the Database from the web, the Database is found through the IP Address: 1158 emconsole.

Symptoms: the Database is open or can be connected to the Database from sqlplus. When you connect to the Database from the web, you can find the Database through the URL http: // IP: 1158/em/console.

Symptoms: the Database is open or can be connected to the Database from sqlplus. When you connect to the Database from the web, you can find the Database Instance, Listener, agent Connect to Instance is normal, but clicking 'database' cannot enter the login page. the error message "Enterprise Manager is not able to connect to the Database instance" is displayed. the state of the components are listed below. ", as shown in:

Solution:

1) connect to the database through sqlplus and check the following user statuses: SYSTEM, SYSMAN, MGMT_VIEW, DBSNMP, and SYS. They should all be open, the problem is that the user is expired or locked.

SQL> select username, account_status from dba_users where username = 'system ';

SQL> select username, account_status from dba_users where username = 'sysmance ';

SQL> select username, account_status from dba_users where username = 'mgmt _ view ';

SQL> select username, account_status from dba_users where username = 'dbsnmp ';

SQL> select username, account_status from dba_users where username = 'sys ';

The locked account is unlocked by running SQL> alter user username account unlock.

The password needs to be reset for an expired account. For dbsnmp and sysman accounts, it is difficult to reset the password. Follow these steps.

Reset dbsnmp account password:
1. SQL> alter user dbsnmp identified by dbsnmp;
2. Find the targets. xml file. Generally, under the $ Oracle_HOME \ hostname_sid \ sysman \ emd directory, modify the following values:
"ENCRYPTED =" FALSE "/>
Restart dbconsole service.

Reset the sysman account password:
1. SQL> alter user sysman identified by sysman;
2. Modify $ ORACLE_HOME \ hostname_sid \ sysman \ config \ emoms. properties. Modify the following two parameters, where [Your encrypted password]
For the current password, the plaintext is enough.
Oracle. sysman. eml. mntr. emdRepPwd = [Your encrypted password]
Oracle. sysman. eml. mntr. emdRepPwdEncrypted = False
Restart dbconsole service.

However, some users will find that this will not solve the problem, and the locked account will be locked again immediately after being unlocked. The reason for this problem is that the password of the account sysman is modified, but the EM end is not followed by a new one, so when you open EM, EM will log on to the instance frantically according to the old password ,, as a result, the wrong password reaches the limit in the user configuration file, and the user is locked. The solution is to change the sysman password in dbconsole. The steps are as follows:

1. Disable dbconsole: emctl stop dbconsole first

2. Change Password: emctl setpasspd dbconsole updates SYSMAN's latest password to DBCONSOLE.

In the DBCONSOLE configuration file: $ ORACLE_HOME \ hostname_instance_name \ sysman \ config \ emoms. in properties, the password project is oracle. sysman. eml. mntr. emdRepPwdSeed = 6685438242677443598. You can only use the preceding command to update the password of SYSMAN.

3 open and console: emctl start dbconsole

Go to EM again and solve the problem.