It is difficult to give a general answer because we do not know what your infrastructure looks like. In this respect, I hope for your understanding. You are welcome to try the following solutions:
- Check if you have installed the latest firmware.
- Try the following settings:
IGMP snooping status - enabled
VLAN ID - do not set
Validate IGMPv3 IP header - disabled
Block unknown multicast address - disabled
Static router port for IGMP snooping - here you enter the number of the port where your router/modem is connected.
If this does not help either, or if these functions are not available, I recommend that you contact Swisscom or Netgear.