Cant SSH Solaris servers

Hi all.
Im working in a telco Environment and recently setup a new server. The other servers are a combination of Solaris + Linux machines.

Using my new server , I can ping all other servers ( solaris + redhat linux )
but the issue lies where I try to ssh.
I can only successfully ssh linux machines but cannot ssh any solaris machine though I can ping them.
Do I need to change any configs on other machines ???

Regards

Are you trying to ssh in as root?

Ive tried all users.

Have you tried ssh -vv username and also look at the logs on the solaris server side.