Came across an annoying bug where all my SSH connections failed:

$ ssh root@52.172.12.100                   
packet_write_wait: Connection to 52.172.12.100 port 22: Broken pipe
$ git clone git@github.com:bycEEE/bycEEE.github.io.git 
Cloning into 'bycEEE.github.io'...
packet_write_wait: Connection to 192.30.253.113 port 22: Broken pipe
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Finally found a discussion on this issue here

Modifying ~/.ssh/config fixed my issues:

Host *
    ServerAliveInterval 600
    TCPKeepAlive yes
    IPQoS=throughput