After upgrading Satellite server from v 5.4 to 5.6, "rhnpush" command fails with "Error Class Code: 2 Invalid username and password combination. "

Issue

• I have upgraded Satellite server from v 5.4 to 5.6 and now rhnpush command is failing with below error message:

# rhnpush -c cust-rhel-x86_64-server-6 --server satellite.example.com /tmp/cust-package-rhel-x86_64-server-6-20140625.0734-0.4.x86_64.rpm 
Red Hat Network username: adsatuser
Red Hat Network password: 
...
Error Class Code: 2  
Error Class Info: Invalid username and password combination.  
Explanation:  
 An error has occurred while processing your request. If this problem  
 persists please enter a bug report at bugzilla.redhat.com.

 If you choose to submit the bug report, please be sure to include  
 details of what you were trying to do when this error occurred and  
 details on how to reproduce this problem.