Needed to downgrade my #Pfsense #Squid #Proxy from 2.8.0 to 2.7.2 because 2.8.0 is setting #Gateways to #Offline for unknown reason. This one has 3 gateways, 1 on WAN, 2 on LAN Interface. Only this VM has Gateway Problems. So no Hardware or Server Stuff.
Bug must be in 2.8.0, because 2.7.2 works without problems and all other VMs on this #proxmox node too.