Failed To Launch Process: Auth Fail During Infiniband Switch Discovery In OEM

Below error is reported during Infiniband switch discovery in Oracle Enterprise Manager (OEM) 12c Release 4 (12.1.0.4.0)

Failed To Launch process: Auth Fail 

However you are able to ssh to same switch using nm2user, without any errors.
This is caused due to the setting "PasswordAuthentication no" in the IB Switch's
/etc/ssh/sshd_config file, which disables clear text password authentication:

#cat /etc/ssh/sshd_config

# To disable tunneled clear text passwords, change to no here!
#PasswordAuthentication yes
# NM2 change - set PermitEmptyPasswords to no
PermitEmptyPasswords no
# NM2 change - set PasswordAuthentication to no
PasswordAuthentication no

Solution :
A workaround to complete the discovery is to include (uncomment) "PasswordAuthentication yes" in the sshd_config file and remove (comment) "PasswordAuthentication no", and restart SSHD using /etc/init.d/sshd restart.