Attempting to backup to my Hetnzer storage box. It supports both sftp and webdav.
I successfully created storage for both ways but when I attempt to create a backup I get “Initialization failure”. I can’t find anything in the logs to see why it’s failing.
I installed Duplicati to see if I have the same problem and on Duplicati it works flawlessly.
Not sure why only Duplicacy is failing 
Run backup with -d flag: duplicacy -d backup, you will get more logging.
I’m using the GUI so I’m not running the command line.
Add -d to global flags of a backup command in the gui.
Then check both duplicacy_web.log and the backup run log.
I see the following:
Reading the environment variable DUPLICACY_SSH_KEY_FILE
Failed to load the SFTP storage at sftp://
Failed to load the SFTP storage at sftp:// ssh: handshake failed: open /home/user/.duplicacy/known:hosts: permission denied
This is the whole log?
Well, here is your answer. check permissions on that file. Have you initialized the repository from the same instance of web ui?
Also, it shall be known_hosts, not known:hosts. Is it accidental edit when copying logs?
I was able to solve the issue. I was providing the password for the sftp server when setting up the storage but because I use an ssh key, I didn’t need to provide the password in the password field!