Backuppc/RsyncD unresponsive on Windows 10

One of my windows backuppc clients is hanging during backups. On the status screen, it shows as "backup in progress" but no transfer PID is shown, and it takes ages in that state. Usually the user shuts down before the backup completes (and the status seems to stay the same). I upgraded RsyncD from 3.0.9 to 3.1.x, applied Windows Updates and rebooted. The next backup seems to have worked (in 80 minutes!) but has been interrupted again. To be checked. It might also be linked to DNS or interface problems (I'm currently migrating the backuppc server from a DHCP to a fixed IP configuration).