Hi guix, Here is a backtrace from mumi.log.zst and mumi.mailer.log.zst. This lead to a 500. ---- mumi.log.zst ERROR: In procedure mu-message-send: In procedure module-lookup: Unbound variable: mu-debug processing job: mail:162506283631699 options: ((from . "Maxime Devos") (subject . "[PATCH] isc-dhcp: Fix dhclient-script wrapper when cross-compiling.") (to . "49293@debbugs.gnu.org") (text . "I forgot to note that I don't have an aarch64-linux-gnu system to test this on. But I did verify the interpreter had the right architecture.")) Backtrace: 3 (primitive-load "/gnu/store/j80xdprnwwcslyq8gnj34jmymid…") In mumi/jobs.scm: 147:19 2 (worker-loop _) 114:18 1 (process-next #) In unknown file: 0 (mu-message-send # …) ---- mumi.mailer.log.zst ERROR: In procedure mu-message-send: In procedure module-lookup: Unbound variable: mu-debug processing job: mail:162506283631699 options: ((from . "Maxime Devos") (subject . "[PATCH] isc-dhcp: Fix dhclient-script wrapper when cross-compiling.") (to . "49293@debbugs.gnu.org") (text . "I forgot to note that I don't have an aarch64-linux-gnu system to test this on. But I did verify the interpreter had the right architecture.")) Backtrace: 3 (primitive-load "/gnu/store/j80xdprnwwcslyq8gnj34jmymid…") In mumi/jobs.scm: 147:19 2 (worker-loop _) 114:18 1 (process-next #) In unknown file: 0 (mu-message-send # …) Greetings, Maxime.