bos: unable to build security class (configuring connection security)

I'm having trouble setting up openafs on debian bookworm. I've imported kerberos keys into openafs via akeyconvert -all: sudo asetkey list rxkad_krb5 kvno 4 enctype 17; key is: ???????????????????????????????? rxkad_krb5 kvno 4 enctype 18; key is: ???????????????????????????????????????????????????????????????? All done. I'm now try to use the bos command line, but this fails: $ sudo bos listkeys -server asus.erjoalgo.com bos: unable to build security class (configuring connection security) I have tried building bos from source to better understand the context of the error message. I've only narrowed it down to: function afsconf_ClientAuthToken in auth/authcon.c code = ktc_GetTokenEx(info->name, &tokenSet); function ktc_GetTokenEx in auth/ktc.c: code = PIOCTL(0, VIOC_GETTOK2, &iob, 0); This returns a non-zero code, causing the command line to fail. What could be the reason that the PIOCTL call is failing? Is there any way to get more information? I've tried rebuilding the kernel module as suggested here: sudo dpkg-reconfigure openafs-modules-dkms And restarting the openafs-client service, but this does not change anything. I only noticed some bening-looking warnings in dmesg: [ 20.377862] systemd-fstab-generator: Checking was requested for "/var/cache/openafs.img", but it is not a device. [ 20.676946] systemd: /lib/systemd/system/openafs-client.service:22: Unit uses KillMode=none. This is unsafe, as it disables systemd's process lifecycle management for the service. Please update the service to use a safer KillMode=, such as 'mixed' or 'control-group'. Support for KillMode=none is deprecated and will eventually be removed. [ 49.217272] openafs: loading out-of-tree module taints kernel. [ 49.217278] openafs: module license 'http://www.openafs.org/dl/license10.html ' taints kernel. [ 49.217987] openafs: module verification failed: signature and/or required key missing - tainting kernel I don't see anything interesting in the openafs-client service logs or in syslog: $ sudo journalctl -feu openafs-client May 28 09:03:43 asus systemd: Starting openafs-client.service - OpenAFS client... May 28 09:03:50 asus afsd: afsd: All AFS daemons started. May 28 09:03:50 asus afsd: afsd: All AFS daemons started. May 28 09:03:50 asus systemd: Started openafs-client.service - OpenAFS client. May 28 09:03:52 asus fs: Usage: /usr/bin/fs sysname [-newsys +] [-help] May 28 21:11:53 asus systemd: Stopping openafs-client.service - OpenAFS client... May 28 21:11:54 asus systemd: openafs-client.service: Deactivated successfully. May 28 21:11:54 asus systemd: Stopped openafs-client.service - OpenAFS client. May 28 21:11:54 asus systemd: openafs-client.service: Consumed 2.957s CPU time. May 28 21:11:54 asus systemd: Starting openafs-client.service - OpenAFS client... May 28 21:11:56 asus afsd: afsd: All AFS daemons started. May 28 21:11:56 asus afsd: afsd: All AFS daemons started. May 28 21:11:56 asus fs: Usage: /usr/bin/fs sysname [-newsys +] [-help] May 28 21:11:56 asus systemd: Started openafs-client.service - OpenAFS client. How can I further debug this bos error? openafs 1.8.9-1-debian $ sudo lsmod | grep openafs openafs 2863104 2 $ bos: unable to build security class (configuring connection security)