Rsync permission denied, but vagrant ssh works

[chornobils]

After asking passphrase and creating a droplet Vagrant tries to copy synced folders, and it output is:

UserKnownHostsFile=/dev/null -i 'C:/Users/Admin/.ssh/digocean'" "--exclude" ".vagrant/" "--exclude" ".gitignore" "--exclude" "vendor/" "--exclude" "README.md" "--exclude" ".git" "--exclude" "node_modules/" "/cygdrive/c/Coding/project/" "ubuntu@ip.ip.ip.ip:/var/www/project"
Error: This rsync lacks old-style --compress due to its external zlib.  Try -zz.
Continuing without compression.

Permission denied (publickey).
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(226) [sender=3.1.2]

Vagrantfile:

  override.ssh.private_key_path = '~/.ssh/digocean'
  override.vm.box = 'digital_ocean'
  override.vm.box_url = "https://github.com/devopsgroup-io/vagrant-digitalocean/raw/master/box/digital_ocean.box"
  override.nfs.functional = false
  provider.token = '<TOKEN>'
  provider.ssh_key_name = 'mykey'
  provider.image = 'ubuntu-16-04-x64'
  provider.region = 'fra1'
  provider.size = '512mb'
end
vmconfig.vm.synced_folder "../sites/project", "/var/www/project",
                                  type: "rsync",
                                  rsync__args: ["--verbose", "--archive", "-z"],
                                  rsync__exclude: [".vagrant/", ".gitignore", "vendor/", "README.md", ".git", "node_modules/"]
vmconfig.vm.synced_folder ".", "/vagrant", disabled: true
vmconfig.vm.synced_folder "../provisioners/nginx", "/vagrant/provisioners/nginx"

Moreover, I can login in droplet with vagrant ssh successfully. I tried to remove first synced folder for running rsync without custom parameters, after that Vagrant shows error with 3rd synced folder in output. Also I tried connect with ssh keys and without -o key option, mentioned above ssh -p 22 -i 'C:/Users/Admin/.ssh/digocean' vagrant2@ip.ip.ip.ip, and it connected successfully.

Host Windows 10 x64