Akhirnya gw ngalamin juga ketika mau ssh ke server sendiri dari linux, di tolak karena
RSA key nya sudah berganti, atau server nya berganti dengan ip atau hostname yang sama,

berikut ini pesan error yang keluar
" IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is 31:f8ab:c5:24:6d:922:eb:63:87:f7:15:1b:67. Please contact your system administrator. Add correct host key in /home/ghufron/.ssh/known_hosts to get rid of this message. Offending key in /home/ghufron/.ssh/known_hosts:7 RSA host key for www.gufy.web.id has changed and you have requested strict checking. "

Setelah tanya2 teman ASWIN HADINATA (yang insya allah akan dpat RHCE) dapat solusi untuk menghapus data2 base RSA key yang pernah ke simapan, caranya.
echo " " >/home/ghufron/.ssh/known_hosts

Akhirnya server bisa di SSH kembali dengan RSA yang baru.
Thanks to Aswin Hadinata