If Debian 12 has been installed with minimal network boot CD/ISO/USB then it probably does not include bridge-utils which is mandatory component to get vmbr bridges to work.
Make sure you install it with apt install bridge-utils first then fix these files /etc/hosts and /etc/network/interfaces (no DHCP.)
After that proxmox-manager should install fine.
I recommend that bridge-utils will be added among postifix and iscsi.
Make sure you install it with apt install bridge-utils first then fix these files /etc/hosts and /etc/network/interfaces (no DHCP.)
After that proxmox-manager should install fine.
I recommend that bridge-utils will be added among postifix and iscsi.
