postfix cannot access dovecot config file

I do not receive email because of the below, as mentioned in my mail.log:

Sep 21 07:58:32 WWW postfix/pipe[5118]: 8F5FD605C8: to=<[email protected]>, relay=dovecot, delay=50089, delays=50089/0.04/0/0, dsn=4.3.0, status=deferred (temporary failure. Command output: lda: Error: user [email protected]: Error reading configuration: stat(/etc/dovecot/dovecot.conf) failed: Permission denied (euid=5000(vmail) egid=8(mail) missing +x perm: /etc/dovecot, we're not in group 113(dovecot), dir owned by 8:113 mode=0750) lda: Fatal: Internal error occurred. Refer to server log for more information. )

I tried adding the mail and vmail users to the dovecot (113) group but no no avail.

What worked is adding read and execute access to all for the /etc/dovecot file but I consider that a workaround with possible hazards now or in the future that I cannot foresee.

What would be best practice: add another system user to the dovecot group or is there any other config which should be changed.

Note that I added a vmail user and group which own my vmail directory. These are used in my postfix virtual_uid_maps and virtual_gid_maps settings. Has the mail system user now become redundant?

Here are my postfix and dovecot settings as well as my passwd and group files:

    # See /usr/share/postfix/main.cf.dist for a commented, more complete version

# The first text sent to a connecting process.
smtpd_banner = $myhostname ESMTP $mail_name
biff = no
# appending .domain is the MUA's job.
append_dot_mydomain = no
readme_directory = no

# alias maps
# default includes nis:alias_maps which produces warning in log
alias_maps = hash:/etc/aliases

# SASL parameters
# ---------------------------------

# Use Dovecot to authenticate.
smtpd_sasl_type = dovecot
# Referring to /var/spool/postfix/private/auth
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_sasl_security_options = noanonymous
smtpd_sasl_local_domain =
smtpd_sasl_authenticated_header = yes

# TLS parameters
# ---------------------------------

# The default snakeoil certificate. Comment if using a purchased 
# SSL certificate.
#smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
#smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key

# Uncomment if using a purchased SSL certificate.
smtpd_tls_cert_file=/etc/ssl/certs/****.crt
smtpd_tls_key_file=/etc/ssl/private/****.key

# The snakeoil self-signed certificate has no need for a CA file. But
# if you are using your own SSL certificate, then you probably have
# a CA certificate bundle from your provider. The path to that goes
# here.
smtpd_tls_CAfile=/etc/ssl/certs/bundle_****.crt

smtp_tls_note_starttls_offer = yes
smtpd_tls_loglevel = 1
smtpd_tls_received_header = yes
smtpd_tls_session_cache_timeout = 3600s
tls_random_source = dev:/dev/urandom
#smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
#smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# Note that forcing use of TLS is going to cause breakage - most mail servers
# don't offer it and so delivery will fail, both incoming and outgoing. This is
# unfortunate given what various governmental agencies are up to these days.
#
# Enable (but don't force) all incoming smtp connections to use TLS.
smtpd_tls_security_level = may
# Enable (but don't force) all outgoing smtp connections to use TLS.
smtp_tls_security_level = may

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

# SMTPD parameters
# ---------------------------------

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h
# will it be a permanent error or temporary
unknown_local_recipient_reject_code = 450
# how long to keep message on queue before return as failed.
# some have 3 days, I have 16 days as I am backup server for some people
# whom go on holiday with their server switched off.
maximal_queue_lifetime = 7d
# max and min time in seconds between retries if connection failed
minimal_backoff_time = 1000s
maximal_backoff_time = 8000s
# how long to wait when servers connect before receiving rest of data
smtp_helo_timeout = 60s
# how many address can be used in one message.
# effective stopper to mass spammers, accidental copy in whole address list
# but may restrict intentional mail shots.
smtpd_recipient_limit = 16
# how many error before back off.
smtpd_soft_error_limit = 3
# how many max errors before blocking it.
smtpd_hard_error_limit = 12

# This next set are important for determining who can send mail and relay mail
# to other servers. It is very important to get this right - accidentally producing
# an open relay that allows unauthenticated sending of mail is a Very Bad Thing.
#
# You are encouraged to read up on what exactly each of these options accomplish.

# Requirements for the HELO statement
smtpd_helo_restrictions = permit_mynetworks, warn_if_reject reject_non_fqdn_hostname, reject_invalid_hostname, permit
# Requirements for the sender details
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, warn_if_reject reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unauth_pipelining, permit
# Requirements for the connecting server
smtpd_client_restrictions = reject_rbl_client sbl.spamhaus.org, reject_rbl_client blackholes.easynet.nl
# Requirement for the recipient address. Note that the entry for
# "check_policy_service inet:127.0.0.1:10023" enables Postgrey.
smtpd_recipient_restrictions = reject_unauth_pipelining, permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, check_policy_service inet:127.0.0.1:10023, permit
smtpd_data_restrictions = reject_unauth_pipelining
# This is a new option as of Postfix 2.10, and is required in addition to
# smtpd_recipient_restrictions for things to work properly in this setup.
smtpd_relay_restrictions = reject_unauth_pipelining, permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, check_policy_service inet:127.0.0.1:10023, permit

# require proper helo at connections
smtpd_helo_required = yes
# waste spammers time before rejecting them
smtpd_delay_reject = yes
disable_vrfy_command = yes

# General host and delivery info
# ----------------------------------

myhostname = mail.****
# mydomain = ****
myorigin = /etc/hostname
# Some people see issues when setting mydestination explicitly to the server
# subdomain, while leaving it empty generally doesn't hurt. So it is left empty here.
# mydestination = mail.example.com, localhost
mydestination =
# If you have a separate web server that sends outgoing mail through this
# mailserver, you may want to add its IP address to the space-delimited list in
# mynetworks, e.g. as 10.10.10.10/32.
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
mynetworks_style = host

# This specifies where the virtual mailbox folders will be located.
virtual_mailbox_base = /var/vmail
# This is for the mailbox location for each user. The domainaliases
# map allows us to make use of Postfix Admin's domain alias feature.
virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf, mysql:/etc/postfix/mysql_virtual_mailbox_domainaliases_maps.cf
# and their user id
virtual_uid_maps = static:5000
# and group id
virtual_gid_maps = static:5000
# This is for aliases. The domainaliases map allows us to make 
# use of Postfix Admin's domain alias feature.
virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf, mysql:/etc/postfix/mysql_virtual_alias_domainaliases_maps.cf
# This is for domain lookups.
virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps.cf

# Integration with other packages
# ---------------------------------------

# Tell postfix to hand off mail to the definition for dovecot in master.cf
virtual_transport = dovecot
dovecot_destination_recipient_limit = 1

# Use amavis for virus and spam scanning
content_filter = amavis:[127.0.0.1]:10024

# Header manipulation
# --------------------------------------

# Getting rid of unwanted headers. See: https://posluns.com/guides/header-removal/
header_checks = regexp:/etc/postfix/header_checks
# getting rid of x-original-to
enable_original_recipient = no

Dovecot

    ## Dovecot configuration file

# If you're in a hurry, see http://wiki2.dovecot.org/QuickConfiguration

# "doveconf -n" command gives a clean output of the changed settings. Use it
# instead of copy&pasting files when posting to the Dovecot mailing list.

# '#' character and everything after it is treated as comments. Extra spaces
# and tabs are ignored. If you want to use either of these explicitly, put the
# value inside quotes, eg.: key = "# char and trailing whitespace  "

# Most (but not all) settings can be overridden by different protocols and/or
# source/destination IPs by placing the settings inside sections, for example:
# protocol imap { }, local 127.0.0.1 { }, remote 10.0.0.0/8 { }

# Default values are shown for each setting, it's not required to uncomment
# those. These are exceptions to this though: No sections (e.g. namespace {})
# or plugin settings are added by default, they're listed only as examples.
# Paths are also just examples with the real defaults being based on configure
# options. The paths listed here are for configure --prefix=/usr
# --sysconfdir=/etc --localstatedir=/var

# Enable installed protocols
!include_try /usr/share/dovecot/protocols.d/*.protocol

# A comma separated list of IPs or hosts where to listen in for connections. 
# "*" listens in all IPv4 interfaces, "::" listens in all IPv6 interfaces.
# If you want to specify non-default ports or anything more complex,
# edit conf.d/master.conf.
#listen = *, ::

# Base directory where to store runtime data.
#base_dir = /var/run/dovecot/

# Name of this instance. In multi-instance setup doveadm and other commands
# can use -i <instance_name> to select which instance is used (an alternative
# to -c <config_path>). The instance name is also added to Dovecot processes
# in ps output.
#instance_name = dovecot

# Greeting message for clients.
#login_greeting = Dovecot ready.

# Space separated list of trusted network ranges. Connections from these
# IPs are allowed to override their IP addresses and ports (for logging and
# for authentication checks). disable_plaintext_auth is also ignored for
# these networks. Typically you'd specify your IMAP proxy servers here.
#login_trusted_networks =

# Space separated list of login access check sockets (e.g. tcpwrap)
#login_access_sockets = 

# With proxy_maybe=yes if proxy destination matches any of these IPs, don't do
# proxying. This isn't necessary normally, but may be useful if the destination
# IP is e.g. a load balancer's IP.
#auth_proxy_self =

# Show more verbose process titles (in ps). Currently shows user name and
# IP address. Useful for seeing who are actually using the IMAP processes
# (eg. shared mailboxes or if same uid is used for multiple accounts).
#verbose_proctitle = no

# Should all processes be killed when Dovecot master process shuts down.
# Setting this to "no" means that Dovecot can be upgraded without
# forcing existing client connections to close (although that could also be
# a problem if the upgrade is e.g. because of a security fix).
#shutdown_clients = yes

# If non-zero, run mail commands via this many connections to doveadm server,
# instead of running them directly in the same process.
#doveadm_worker_count = 0
# UNIX socket or host:port used for connecting to doveadm server
#doveadm_socket_path = doveadm-server

# Space separated list of environment variables that are preserved on Dovecot
# startup and passed down to all of its child processes. You can also give
# key=value pairs to always set specific settings.
#import_environment = TZ

##
## Dictionary server settings
##

# Dictionary can be used to store key=value lists. This is used by several
# plugins. The dictionary can be accessed either directly or though a
# dictionary server. The following dict block maps dictionary names to URIs
# when the server is used. These can then be referenced using URIs in format
# "proxy::<name>".

dict {
  #quota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
  #expire = sqlite:/etc/dovecot/dovecot-dict-sql.conf.ext
}

# Most of the actual configuration gets included below. The filenames are
# first sorted by their ASCII value and parsed in that order. The 00-prefixes
# in filenames are intended to make it easier to understand the ordering.
!include conf.d/*.conf

# A config file can also tried to be included without giving an error if
# it's not found:
!include_try local.conf

passwd

    root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
man:x:6:12:man:/var/cache/man:/usr/sbin/nologin
lp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologin
mail:x:8:8:mail:/var/vmail:/usr/sbin/nologin
news:x:9:9:news:/var/spool/news:/usr/sbin/nologin
uucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologin
proxy:x:13:13:proxy:/bin:/usr/sbin/nologin
www-data:x:33:33:www-data:/var/www:/usr/sbin/nologin
backup:x:34:34:backup:/var/backups:/usr/sbin/nologin
list:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologin
irc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologin
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologin
nobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologin
libuuid:x:100:101::/var/lib/libuuid:
syslog:x:101:104::/home/syslog:/bin/false
mysql:x:102:106:MySQL Server,,,:/nonexistent:/bin/false
messagebus:x:103:107::/var/run/dbus:/bin/false
postfix:x:104:111::/var/spool/postfix:/bin/false
dovecot:x:105:113:Dovecot mail server,,,:/usr/lib/dovecot:/bin/false
dovenull:x:106:114:Dovecot login user,,,:/nonexistent:/bin/false
landscape:x:107:115::/var/lib/landscape:/bin/false
sshd:x:108:65534::/var/run/sshd:/usr/sbin/nologin
myuser:x:1000:1000:MYUSER,,,:/home/myuser:/bin/bash
vmail:x:5000:8::/var/vmail:
clamav:x:109:118::/var/lib/clamav:/bin/false
postgrey:x:110:119::/var/lib/postgrey:/bin/false
amavis:x:111:120:AMaViS system user,,,:/var/lib/amavis:/bin/sh
debian-spamd:x:112:121::/var/lib/spamassassin:/bin/sh

group

    root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:syslog
tty:x:5:
disk:x:6:
lp:x:7:
mail:x:8:
news:x:9:
uucp:x:10:
man:x:12:
proxy:x:13:
kmem:x:15:
dialout:x:20:
fax:x:21:
voice:x:22:
cdrom:x:24:user
floppy:x:25:
tape:x:26:
sudo:x:27:user
audio:x:29:
dip:x:30:user
www-data:x:33:
backup:x:34:
operator:x:37:
list:x:38:
irc:x:39:
src:x:40:
gnats:x:41:
shadow:x:42:
utmp:x:43:
video:x:44:
sasl:x:45:
plugdev:x:46:user
staff:x:50:
games:x:60:
users:x:100:
nogroup:x:65534:
libuuid:x:101:
netdev:x:102:
crontab:x:103:
syslog:x:104:
fuse:x:105:
mysql:x:106:
messagebus:x:107:
mlocate:x:108:
ssh:x:109:
ssl-cert:x:110:
postfix:x:111:
postdrop:x:112:
dovecot:x:113:mail,vmail
dovenull:x:114:
landscape:x:115:
web:x:1000:www-data
lpadmin:x:116:
sambashare:x:117:
clamav:x:118:amavis
postgrey:x:119:
amavis:x:120:clamav
debian-spamd:x:121:
vmail:x:5000: