Sent with Proton Mail secure email. On Monday, 23 December 2024 at 12:23, Adam Nielsen <a.nielsen@xxxxxxxxxxx> wrote: > But what's the underlying issue? Maybe there's a different fix? Its been a while so I can't remember the exact details, but I know its to do with Postfix. Postfix creates a copy (not symlink) of /etc/resolv.conf in its /var/spool/postfix jail. If the jail file contains 127.0.0.53 email is broken. If changed to 127.0.0.54 email works. As I said, its been a long time, but IIRC the underlying reason is something to do with DNNSEC validation and systemd-resolved breaks it with the 127.0.0.53 proxy.