ssh_exchange_identification: Соединение закрыто удаленным хостом

Я новичок в серверах, так что извините, если это глупый вопрос. Я купил новый Mac и загрузил файл пары ключей ssh ​​для Amazon AWS EC2 из своего Dropbox.

Я пытался подключиться к серверу как обычно:

ssh-add ~/.filename.pem 
Identity added: ....
ssh ubuntu@myserverpublicndsaddress.amazonaws.com
ssh_exchange_identification: Connection closed by remote host

Я также пытался получить некоторую информацию:

ssh -vv ubuntu@myserverpublicndsaddress.amazonaws.com
OpenSSH_7.6p1, LibreSSL 2.6.2
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to myserverpublicndsaddress.amazonaws.com port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/user/.ssh/id_ed25519-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6
ssh_exchange_identification: Connection closed by remote host

Кто-нибудь может помочь с проблемой?