ASM instance shows 'Down' in OEM 13.2 after upgraded to 12.2

Standalone Grid Infrastruture (Oracle Restart) is upgraded to 12.2 and everything works well. However, the ASM instance shows 'Down' in Enterprise Manager 13.2.

Checked 'Monitoring Configuration' of ASM target, all information is correct and 'Test Connection' succeeds.  We can log into ASM instance page in OEM to do management tasks (creat/drop diskgroup, etc). Everything looks good except the Target Status.

Log onto the host where ASM is running on, and run following commands from OEM agent home:

1. Get the target name of ASM instance
$ emctl config agent listtargets | grep ASM
[+ASM_host01.dbaplus.ca, osm_instance]


2. Find out the 'real time' results of the 'REsponse' metric (test connection from local agent to target)
$ emctl getmetric agent +ASM_host01.dbaplus.ca,osm_instance,Response
Oracle Enterprise Manager Cloud Control 12c Release 5 
Copyright (c) 1996, 2015 Oracle Corporation.  All rights reserved.
Status,oraerr
0,Failed to connect: java.sql.SQLException: ORA-28040: No matching authentication protocol

Wow, '0' is returned with 'ORA-28040'. I believe many DBAs saw error 28040 when upgrading their databases to 12c. OEM agent (12c Release 5) is using old Oracle client (10g) to access ASM instance which is running on 12.2.

Solution:
Add following lines to $GRID_HOME/network/admin/sqlnet.ora
SQLNET.ALLOWED_LOGON_VERSION_SERVER=10
SQLNET.ALLOWED_LOGON_VERSION_CLIENT=10 
Test the connection again:
$emctl getmetric agent +ASM_host01.dbaplus.ca,osm_instance,Response
Oracle Enterprise Manager Cloud Control 12c Release 5 
Copyright (c) 1996, 2015 Oracle Corporation.  All rights reserved.
Status,oraerr
1, 

'1' is returned and indicates that the ASM  is up and running. 

And the ASM target shows 'Up' in OEM.