can't authenticate

[David Matthews]

My live mail exchanger and development machines have identical dovecot setups, yet I cannot login on the development machine:-

dovecot --version
2.3.13 (89f716dc2)

>telnet localhost 143
Trying 127.0.0.1...
Connected to bulawayo.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ STARTTLS AUTH=PLAIN] Dovecot (Debian) ready.
a login fred xxxxxxxxxxx
a NO [UNAVAILABLE] Temporary authentication failure. [bulawayo:2022-01-26 20:02:14]

same if I try openssl s_client to 993

>tail /var/log/mail.log
Jan 26 20:03:28 bulawayo dovecot: imap-login: Disconnected (auth service reported temporary failure): user=<fred>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, secured, session=<1MRorYHWwOp/AAAB>

doveconf -n
# 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.13 (cdd19fe3)
# OS: Linux 5.10.0-10-amd64 x86_64 Debian 11.1 
# Hostname: bulawayo
mail_location = mbox:~/mail:INBOX=/var/mail/%u
mail_privileged_group = mail
namespace inbox {
  inbox = yes
  location = 
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    special_use = \Junk
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix = 
}
passdb {
  driver = pam
}
protocols = " imap"
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
ssl_cert = </etc/dovecot/private/dovecot.pem
ssl_client_ca_dir = /etc/ssl/certs
ssl_dh = # hidden, use -P to show it
ssl_key = # hidden, use -P to show it
userdb {
  driver = passwd
}

--
David Matthews
mail at dmatthews.org