netbsd
Server refused to allocate pty (NetBSD PV guest but probably related to PV Linuxes as well)
If you faced this kind of error on your terminal login as: **** Keyboard-interactive authentication prompts from server: | Password for ****@hostname.tld: End of keyboard-interactive prompts from server Server refused to allocate pty especially often in PV guest of XEN this means that there are no available terminals you can be