Client:

kex_exchange_identification: read: Connection reset by peer
Connection reset by 159.195.22.112 port 22

Server:

$ journalctl -efu ssh
[...]
drop connection #10 from [212.99.194.59]:59789 on [159.195.22.112]:22 Maxstartups

$ man sshd_config:

MaxStartups

Specifies the maximum number of concurrent unauthenticated connections to the SSH daemon. Additional connections will be dropped until authentication succeeds or the LoginGraceTime expires for a connection. The default is 10:30:100. Alternatively, random early drop can be enabled by specifying the three colon separated values start:rate:full (e.g. "10:30:60"). sshd(8) will refuse connection attempts with a probability of rate/100 (30%) if there are currently start (10) unauthenticated connections. The probability increases linearly and all connection attempts are refused if the number of unauthenticated connections reaches full (60).