Custom build md5_server times out for some md5_clients

[mtbrobotanist]

I wrote my own md5_server following the logic of the example bin/md5_server.c and spam it with 100 clients in parallel. Each client passes a 160K file to the server. Sometimes, some of the clients time out. I have attached the server log and the clients log. each client runs in its own process. both server and clients are running on the same host. The issue is reproducible.
The example bin/md5_server takes more clients before it can't handle some, eventually it does the same too.

This log has 1 failed client, visible at the bottom of the file. The connection id is present in the client log, but not the server log:

98903C2C44453433

I do not yet understand the protocol well enough. Is there enough information to see why the connection timed out?

server.txt

client.txt