Hass.IO spontaneous dropsouts on various services? Troubleshoot

PROBLEM:
I’m experiencing spontaneous dropsouts on various services… It happens a couple of times each day.
It’s not just one particular device.
Can someone give me some guidence on how to troubleshoot some more?

Setup:
INTEL NUC
Proxmox
Home Assistant OS (HASSIO Hassosova-4.12)

LOGS:
[satel_integra.satel_integra] Got exception: [Errno 104] Connection reset by peer. Most likely the other side has disconnected!
2020-09-07 02:31:55 WARNING (Thread-43) [pychromecast.socket_client] [Chromecast Stue(192.168.1.131):8009] Heartbeat timeout, resetting connection
2020-09-07 04:19:33 WARNING (Thread-42) [pychromecast.socket_client] [Soveværelse 2(192.168.1.176):8009] Heartbeat timeout, resetting connection
2020-09-07 04:33:03 WARNING (Thread-40) [pychromecast.socket_client] [Google Home Køkken(192.168.1.132):8009] Heartbeat timeout, resetting connection

WHAT I’VE TRIED SO FAR:
-Upgrade NUC bios
-Disabled offload functionality on NIC on Proxmox host. ethtool -K vmbr0 gso off gro off tso off
-Fixated Proxmox Host NIC @1GBit Full duplex.
-Changed adaptor of virtual machine (HassOS) from VirtIO > e1000 type.
-Replaced network cable.

Any guidence on where to look would be highly appreciated.

Thanks
R. Bach

My Chromecast audio has that heartbeat timeout once per day. Never worked out why.

Does your error log give the same warning ?

Yes I get the Heartbeat timeout, resetting connection message once a day. It works fine though.