SSH connection did not reach command prompt

Sometimes when signing in, I see these messages (in verbose mode), and jupyter-o2 immediately exits.
```
Responding to Duo 2FA prompt
Found prompt #0
SSH connection did not reach command prompt.
```
This happens a couple of times in a row, but the same command usually works on the third try. Will need to investigate why this is happening, but in the mean time, a few retries works for me.