Players are timing out mid-session
What it looks like in your log
lost connection: Timed out
What causes it
The client stopped answering keepalive packets inside the 30 second window, so the server dropped the connection.
How to fix it
If one player drops and others do not, it is that player’s connection. If several drop on the same timestamp, the server froze for those 30 seconds; look at what stalls the tick loop (chunk generation, a mod hang, or a garbage collection pause on a heap that is too small) rather than the network.
Not sure this is your problem? Paste your log and Roastd will tell you which of these it actually matched, and what else it found.
Check your own log