opening a standard ssh session not working

[disk91]

ssh root@10.0.0.143
root@10.0.0.143's password:
PTY allocation request failed on channel 0

/dev/pts does not exists.

workaround:
ssh root@10.0.0.143 /bin/ash -i
root@10.0.0.143's password:
/bin/ash: can't access tty; job control turned off
/root #