SSHError Code=4 "Failed getting banner"

could you connect to your server using ssh clint with verbose output and post results here? (do not forget to strip out all sensitive info)

ssh -v hostname

Unfortunately, I do not have root access to my client.

you do not need to have root access. Just execute this command from Terminal on your mac.
It will connect you to your host and produce connection information.

This is the output on my computer:

OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
ssh: Could not resolve hostname hostname: nodename nor servname provided, or not known
Someones-MacBook-Pro:~ someone$

ssh -v ******.seedstuff.ca -P 443

instead of ******.seedstuff.ca use your host name

I get this output:

ssh -v ******.seedstuff.ca -P 443

OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to ******.seedstuff.ca [12.34.56.78] port 22.
debug1: connect to address 12.34.56.78 port 22: Connection refused
ssh: connect to host ******.seedstuff.ca port 22: Connection refused

I changed the IP address of my seedbox host and obscured the hostname.

I do not understand why it is trying to connect at port 22. Shouldn't it be 443?

sorry, my bad: use -p, not -P

ssh -v ******.seedstuff.ca -p 443

Ok, here's the output for that:

Someones-MacBook-Pro:~ someone$ ssh -v ******.seedstuff.ca -p 443
OpenSSH_6.9p1, LibreSSL 2.1.8
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to ******.seedstuff.ca [12.34.56.78] port 443.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /Users/someone/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.9
ssh_exchange_identification: Connection closed by remote host

it seems you unable to connect your server.
Probably cause of your server does not support password authentication.
Native currently does not support key based authentication.