Hi,

I am getting the following error while authenticating any user, using SASL with postfix, please help me to fix this issue.

May 08 17:34:50 master: Info: Dovecot v2.2.36.4 (baf9232c1) starting up for imap, pop3, lmtp, sieve (core dumps disabled)
May 08 17:35:10 master: Error: service(auth): command startup failed, throttling for 2 secs
May 08 17:35:10 auth: Fatal: master: service(auth): child 6969 killed with signal 11 (core dumps disabled)

root@mail:/usr/local/dovecot/etc/dovecot/conf.d# /usr/local/dovecot/sbin/dovecot -n
# 2.2.36.4 (baf9232c1): /usr/local/dovecot/etc/dovecot/dovecot.conf
# Pigeonhole version 0.4.24.2 (aaba65b7)
# OS: Linux 4.19.0-16-amd64 x86_64 Debian 10.9
# Hostname: mail.example.com
auth_default_realm = example.com
auth_mechanisms = plain login
base_dir = /usr/local/dovecot/var/run/dovecot/
default_client_limit = 5000
default_process_limit = 500
default_vsz_limit = 512 M
first_valid_uid = 1001
last_valid_uid = 1001
listen = 127.0.0.1
lmtp_save_to_detail_mailbox = yes
log_path = /var/log/imap
login_greeting = Messaging Server
mail_gid = 1001
mail_location = maildir:/%Lh/Maildir/:INDEX=/%Lh/Maildir/
mail_plugins = quota acl fts fts_lucene
mail_uid = 1001
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date index ihave duplicate mime foreverypart extracttext vacation-seconds imapflags notify
namespace inbox {
  inbox = yes
  location =
  mailbox Archive {
    auto = subscribe
    special_use = \Archive
  }
  mailbox "Deleted Items" {
    special_use = \Trash
  }
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox "Junk E-mail" {
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox "Sent Items" {
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix =
  separator = .
  type = private
}
passdb {
  args = /usr/local/dovecot/etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
plugin {
  acl = vfile:/usr/local/dovecot/dovecot-acl/acl
  acl_shared_dict = file:/maildir/domains/dovecot/shared-mailboxes/shared-mailboxes.db
  fts = lucene
  fts_autoindex = yes
  fts_lucene = whitespace_chars=@.
  fts_tika = http://localhost:9997/tika/
  quota = maildir:User quota
  quota_rule = *:storage=1G
  quota_warning = storage=85%% quota-warning 85 %u
  quota_warning2 = storage=90%% quota-warning 90 %u
  quota_warning3 = storage=95%% quota-warning 95 %u
  sieve = ~/.dovecot.sieve
  sieve_after = /usr/local/dovecot/sieve/default.sieve
  sieve_before = ~/sieve/01_vacation.sieve
  sieve_dir = ~/sieve
  sieve_extensions = +notify +imapflags +vacation +vacation-seconds
  sieve_global_dir = /usr/local/dovecot/sieve/
  sieve_quota_max_scripts = 5
  sieve_vacation_send_from_recipient = yes
  sieve_vacation_use_original_recipient = yes
}
pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
protocols = imap pop3 lmtp sieve
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postfix
    mode = 0660
    user = postfix
  }
  unix_listener auth-userdb {
    group = vmail
    mode = 0666
    user = vmail
  }
}
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    address = *
    port = 993
    ssl = yes
  }
}
service imap-postlogin {
  executable = script-login /usr/local/dovecot/bin/postlogin.sh
  user = root
}
service imap {
  executable = /usr/local/dovecot/libexec/dovecot/imap imap-postlogin
}
service lmtp {
  executable = lmtp -L
  inet_listener lmtp {
    address = 127.0.0.1 ::1
    port = 7025
  }
  process_min_avail = 5
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0600
    user = postfix
  }
  user = vmail
}
service managesieve-login {
  inet_listener sieve-obsolete {
    port = 2000
  }
}
service pop3-login {
  inet_listener pop3 {
    port = 110
  }
  inet_listener pop3s {
    address = *
    port = 995
    ssl = yes
  }
}
service quota-warning {
  executable = script /usr/local/dovecot/bin/quota-warning.sh
  unix_listener quota-warning {
    group = vmail
    mode = 0660
    user = vmail
  }
}
service stats {
  unix_listener stats-reader {
    group = vmail
    mode = 0660
    user = vmail
  }
  unix_listener stats-writer {
    group = vmail
    mode = 0660
    user = vmail
  }
}
ssl = required
ssl_ca = </etc/ssl/localcerts/intermediate.crt
ssl_cert = </etc/ssl/localcerts/mail.crt
ssl_key =  # hidden, use -P to show it
submission_host = 127.0.0.1
userdb {
  args = /usr/local/dovecot/etc/dovecot/dovecot-ldap.conf.ext
  driver = ldap
}
protocol lmtp {
  mail_plugins = quota acl fts fts_lucene sieve
}
protocol sieve {
  managesieve_logout_format = bytes ( in=%i : out=%o )
}
protocol lda {
  info_log_path = /var/log/dovecot-lda.log
  log_path = /var/log/dovecot-lda-errors.log
  mail_plugins = quota acl fts fts_lucene sieve virtual
}
protocol imap {
  mail_max_userip_connections = 50
  mail_plugins = quota acl fts fts_lucene imap_quota  imap_acl
}

Thanks, Regards