The authentication of users in the platform relies on Kerberos.
If you log in the gateway using a password, the Kerberos authentication is automatically used behind the scenes.
However, if you authenticate to the gateway with another mean (such as a RSA private/public key pair), Kerberos is not used and you will be authenticated only to the gateway machine. You will thus need to authenticate to the cluster using Kerberos by getting an autentication ticket.
You can do that with the command kinit which will prompt you for a password. You can verified if you curently hold a ticket using command klist.

Trying to interact with the cluster without a valid ticket will cause an error such as this one : GSS initiate failed [Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)]