Error Message: Can't call method min_digest_id on an undefined value

The following pmx-qdigest error may be caused by a corrupted quarantine scan database (/opt/pmx/var/qdigest/scan.db).

Can't call method "min_digest_id" on an undefined value /opt/pmx/bin/pmx-qdigest line n
Related tasks
Digests Are Not Generated
Some Users Are Not Receiving Digests
Users Can't Release Quarantined Messages