We recommend rebooting the server were the Directory Sync agent is installed, We've seen instances were network share sessions become stale and stuck, restarting should break all the sessions and allow for a new one to be generated.
Also, the following error: "Read: Error connecting to remote share (WNetAddConnection2 error code: 1219)" indicates Access Denied.
This mean that the account to install the dirsync agent does not have permission to access to copy and to execute it on the DC. The service account should be added as a Built-in\Administrator on the target Domain Controller.Built-In admin group.
Verify the account required have a appropriate right given as required on this online help: https://support.quest.com/technical-documents/on-demand-migration/current/active-directory-user-guide#TOPIC-1676287
