"Connection closed by remote host" and/ or "Broken pipe" message and copy errors might be returned by SSH on the remote server. This does not happen on the reference Linux distros: RHEL, Fedora, CentOS and is caused by some particularities in the behaviour of the SSH daemon shipped with ESXi. We are working on it and will release a fix with version 11.2.3.
This error is due to some changes in the keep alive policy of the SSH server in the sshd_config file. You can easily tweak that to prevent these errors by increasing the keep alive interval. We might include this adjustments to be performed by XSIBACKUP-PRO in some future version, although being something affecting your security profile, we'll leave it to the sysadmin by now.