AWS BigIP VE SSH root login failure

I've spun up another appliance in a different VPC in a different region, with a different SSH key that I've already used on other EC2 instances, I've tried connecting directly from my mac and via a jumphost. When I try to connect:

 

$ ssh -i sshkey.pem root@xxx.xxx.xxx.xxx

 

The authenticity of host 'xxx.xxx.xxx.xxx (xxx.xxx.xxx.xxx)' can't be established.

 

RSA key fingerprint is xx:xx:xx:xx:xx:xx.

 

Are you sure you want to continue connecting (yes/no)? yes

 

Warning: Permanently added 'xxx.xxx.xxx.xxx' (RSA) to the list of known hosts.

 

Connection closed by xxx.xxx.xxx.xxx

 

:o(

 

I must be doing something very very simple, very very wrong. Please enlighten me.

 

More verbose debug SSH info I can provide.