ssh cannot connect to an old linux server

I have a server CentOS release 6.6, I am using an application called "CounterACT" to connect. I got the following error message. However, when i use the same software to connect a new build Centos 7 box, it runs smoothly. I was wondering something is running on the old centos 6 box forbidding the connection.

Please help. thank you.



Warning: Permanently added '172.16.150.7' (RSA) to the list of known hosts.
********************* XXXX Legal Notification ***************************
This computer system and the information it contains are the property of 
XXX and may be accessed solely by authorized users. 

Authorized users may not access or use this system or the information it con-
tains beyond the scope of their authorization. Unauthorized access or use may 
result in disciplinary action and/or civil and criminal penalties. 

By accessing this computer system, you agree that :i you will comply with 
XXX's policies, including XXXs Information Technology Security 
Policies and Procedures, (ii) XXXmay transfer and store information 
internationally, including in the United States, and (iii) to the extent per-
mitted by law, XXX may monitor all activity and information on its sys-
tems and may disclose information for legal and other purposes. 

Any questions about this policy should be addressed to ITG or to the Regional 
Vice President of Human Resources.
*******************************************************************************
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,keyboard-interactive).
lost connection