I'm running OMV 5.6.26-1 on Debian 10 as QEMU/KVM virtual machine on Ubuntu 20.04.4. I have setup bridged network on Ubuntu and assigned two dedicated IP addresses, one for the host and one for the guest. Host and guest get their IPs from FritzBox DHCP in a static manner. In general it works well but occasionally I was not able to access the server using its name.
I thought the problems are caused by the active IPv6 DHCP server on the router, so I disabled IPv6 on the router. But with only IPv4 it has become even worse. I can ping the host using its name, but the guest only by using the assigned IP. No chance to reach it via its name.
What can cause this and what could I try to solve it?