There is a known issue when using servers with multiple network interfaces in use (e.g. one NIC for server connection and another NIC for a calibration camera). All connected servers might show content once paused, but show just black as soon as playback is started.

Considering, that all content is properly transferred, the reason for this might be a wrong network binding for the communication between master and clients. To solve this, the multicast binding must be corrected:

Via Windows command-line:

route add 224.0.0.0 mask 240.0.0.0 X.X.X.X“
replace X.X.X.X with the IP of the currently used NIC .

To set this binding permanently:

route -p add 224.0.0.0 mask 240.0.0.0 X.X.X.X
replace X.X.X.X with the IP of the currently used NIC .

See attached a script that helps you to execute these tasks.