We appreciate your continued patience as we work through these problems. Thank you.
The email issue for a small subset of machines is related to the Dovecot v2.4 upgrade, and cPanel proxying auth via their internal cpauthd/cpsrvd binaries instead of “as usual” via passwd/shadow files and so on. There is a caching fault within cpauthd which leads to spurious “user unknown” errors for perfectly valid mailbox users - exploring the code responsible shows that it was AI-made without proper understanding by cP’s product team.
The access problem we’re now re-focusing on, targeting normal service by/on Monday at this time.