If you leave off "http" or "https" from conduit, we guess the URI to be "ssh" instead of failing that the URI is missing a protocol. Possibly related to 8bb124c37de3
seth@dev2:~/tmp$ ./arcanist/bin/arc install-certificate 'secure.phabricator.com:8001/'
CONNECT Connecting to "secure.phabricator.com:/api/"...
LOGIN TO PHABRICATOR
Open this page in your browser and login to Phabricator if necessary:
secure.phabricator.com:/conduit/login/
Then paste the API Token on that page below.
Paste API Token from that page: ^C