for "reboot in 60" the format is not correct.
it should be reboot in <minutes> and not <HH:MM>
```
labuser@lab01:~$ reboot in 60
Invalid time "60". The valid format is HH:MM
labuser@lab01:~$ reboot in
Possible completions:
<Minutes> Reboot in X minutes
labuser@lab01:~$ reboot in 1:00
Reboot is scheduled 2020-11-14 01:00:00
```