HA Blue loosing connection - Network unreachable

Hello,

My HA Blue is loosing connection in every couple of days (2-3).
If I log in to the admin page of the router, the Blue is not visible. The Ethernet LEDs on the Blue are still flashing.

After I unplug and replug the Ethernet cable it can reconnect to the network.

Core: 2021.10.6
Supervisor: 2021.10.6

Error message:

2021-11-03 19:42:20 ERROR (MainThread) [async_upnp_client.ssdp] Received error: [Errno 101] Network unreachable, transport: <_SelectorDatagramTransport fd=26 read=polling write=<idle, bufsize=0>>
2021-11-03 19:42:21 ERROR (MainThread) [async_upnp_client.ssdp] Received error: [Errno 101] Network unreachable, transport: <_SelectorDatagramTransport fd=29 read=polling write=<idle, bufsize=0>>
2021-11-03 19:42:21 ERROR (MainThread) [async_upnp_client.ssdp] Received error: [Errno 101] Network unreachable, transport: <_SelectorDatagramTransport fd=29 read=polling write=<idle, bufsize=0>>
2021-11-03 19:43:20 ERROR (MainThread) [async_upnp_client.ssdp] Received error: [Errno 101] Network unreachable, transport: <_SelectorDatagramTransport fd=26 read=polling write=<idle, bufsize=0>>
2021-11-03 19:43:21 ERROR (MainThread) [async_upnp_client.ssdp] Received error: [Errno 101] Network unreachable, transport: <_SelectorDatagramTransport fd=29 read=polling write=<idle, bufsize=0>>

Any suggestions?
Thank you.

Core is updated to 2021.11.3, but the issue still exists.

Update: The Blue is connected to a switch with a short cable, however the switch is connected to the main router with a longer, 40ft cable. As the longer cable might be the issue, I connected the Blue directly to the router with a short (3ft) cable, but unfortunately, it didnt solve the problem.

Any ideas?