The Minecraft console is unresponsive to any form of interaction - via the webUI or screen.
The server works fine and I can watch the output from the console, but not enter keypresses.
If you are using Ubuntu 18.04, please note that the following kernel appears to have issues handling console input:
4.15.0-44-generic #47-Ubuntu SMP Mon Jan 14 11:26:59 UTC 2019.
Older (e.g. 4.15.0-43-generic #46-Ubuntu SMP Thu Dec 6 14:45:28 UTC 2018) kernels are not affected.
If you are using this kernel and have a message along the lines of “java.io.IOException: Resource temporarily unavailable”, this is the reason.
We are still investigating the exact cause / reason for this.
If you are affected by this issue there are a number of workarounds available (you only need to use one).
Spigot / BungeeCord: Add -Djline.terminal=jline.UnsupportedTerminal to your Java arguments
Spigot: Add --nojline to your Spigot arguments
Reboot your server and select 4.15.0-43, or any other non broken Linux kernel.
Install a non broken kernel: apt install linux-image-4.15.0-43-generic, remove the broken one: apt remove linux-image-4.15.0-44-generic, and reboot.