ORA-12523, TNS:listener could not find instance appropriate for the client connection when adding Oracle ASM agent (4359226)

Following error is found in the Oracle installer log when adding an Oracle ASM agent:

ECHO ERROR [pool-19-thread-1] com.quest.qsi.dbwc.AutoDiscovery.verify.AbstractVerify - Exception:ora_verikey1448441972756failed connect to hostname-+ASM2 status: CONNECTION_STATUS_DB_ERROR{1} com.quest.qsi.fason.framework.connections.common.exceptions.FrameworkException: Failed to establish a Oracle JDBC connection protocol to Host [hostname-+ASM2], user account [quest_fog] . Reason : [Listener refused the connection with the following error: ORA-12523, TNS:listener could not find instance appropriate for the client connection - Profile:OracleProfile{host='hostname', instance='+ASM2', service='+ASM', username='quest_fog', userType=sysasm, ports='3031'}]. . [Oracle Error Code = 12523. SQL state : 66000]

ORA-12523 normally happens if the listener is not running or the connection is not setup properly.

1.  On the ASM host, if you run 'lsnrctl status', do you see the ASM service?
2.  Are you also able to connect the each of the ASM node via sqlplus as the sysasm user?
3.  Are you able to tnsping the ASM instance? 

If there are issues with the above, consult your Oracle documentation on how to rectify them.