Ubuntu 18.04 rsync method fails

Hello,

I am using gem "middleman-deploy", "~> 2.0.0.pre.alpha", SSH sign to my Digital Ocean server works but when I try to deploy code with your middleman deploy command through RSYNC, I am getting:

Project built successfully.
## Deploying via rsync to USER@XXX.XXX.XXX.XXX:/home/XXXXXXX/www/XXXXXXXX.com port=22
USER@XXX.XXX.XXX.XXX: Permission denied (publickey).
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at /BuildRoot/Library/Caches/com.apple.xbs/Sources/rsync/rsync-52/rsync/io.c(453) [sender=2.6.9]

I am not sure why is that if the permissions for the directory are chmod 777, also, same setup on Ubuntu 16.04 and your middleman-deploy works just fine.