Please see these instructions
Many hosts on campus are behind the University firewall, meaning direct SSH connections from outside the campus network are blocked for security reasons. In most cases, first making a connection to the UDel VPN is sufficient. See the UD IT documentation regarding how to connect to the UDel VPN.
Another option is to first connect to one of our public-facing systems before proceeding to your intended destination. You can also use these computers as a jump-host when connecting to SSH. See your SSH client documentation for configuring this option.
You can use rmdir to delete your snapshot(s), for more information on how to do this see the documentation page. Otherwise please submit a Help Request and let us know which machine you were using. Watch your email for quota warnings.