bad command startup -- throttling

Hello guys, I need really some help.
I have an issue with my mail (Server 2.2.1)

The issue I have are:

- warning: /usr/libexec/postfix/smtpd: bad command startup -- throttling

- merlin.macwebservers.com postfix/smtpd[1144]: fatal: unsafe ownership or permissions on /private/etc/postfix/submit.cred: uid/gid/mode are 0/27/600 should be 0/0/0600

- I have some email but not from gmail, yahho

My postconf -n

alias_database = hash:/etc/aliases

alias_maps = hash:/etc/aliases

biff = no

command_directory = /usr/sbin

config_directory = /etc/postfix

daemon_directory = /usr/libexec/postfix

data_directory = /Library/Server/Mail/Data/mta

debug_peer_level = 2

debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin xxgdb $daemon_directory/$process_name $process_id & sleep 5

default_destination_concurrency_limit = 7

default_privs = nobody

default_transport = smtp

dovecot_destination_recipient_limit = 1

enable_server_options = yes

header_checks = regexp:/etc/postfix/header_checks

html_directory = /usr/share/doc/postfix/html

imap_submit_cred_file = /Library/Server/Mail/Config/postfix/submit.cred

inet_interfaces = all

inet_protocols = all

mail_owner = _postfix

mail_spool_directory = /var/spool/mail

mailbox_command = /usr/bin/procmail

mailbox_size_limit = 0

mailbox_transport = dovecot

mailq_path = /usr/bin/mailq

manpage_directory = /usr/share/man

message_size_limit = 10485760

mydestination = $myhostname

mydomain = macwebservers.com

mydomain_fallback = localhost

myhostname = merlin.macwebservers.com

mynetworks = 127.0.0.0/8, [::1]/128,

myorigin = $mydomain

newaliases_path = /usr/bin/newaliases

postscreen_dnsbl_sites =

queue_directory = /Library/Server/Mail/Data/spool

readme_directory = /usr/share/doc/postfix

recipient_canonical_maps = hash:/etc/postfix/system_user_maps

recipient_delimiter = +

relay_domains = $mydestination $virtual_maps $transport_maps

relayhost =

sample_directory = /usr/share/doc/postfix/examples

sendmail_path = /usr/sbin/sendmail

setgid_group = _postdrop

smtpd_banner = $myhostname ESMTP

smtpd_client_restrictions = check_client_access hash:/etc/postfix/blacklist_smtp

smtpd_enforce_tls = no

smtpd_helo_required = yes

smtpd_helo_restrictions = reject_invalid_helo_hostname reject_non_fqdn_helo_hostname

smtpd_recipient_restrictions = reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, permit_mynetworks, reject_unauth_destination, check_sender_access hash:/etc/postfix/sender_access, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net, check_policy_service unix:postgrey/socket, permit

smtpd_tls_CAfile = /etc/certificates/Alains-Mac-mini.local.0BEEA40E61E3D14D83B7838979EAAE191AF0930 0.chain.pem

smtpd_tls_cert_file = /etc/certificates/Alains-Mac-mini.local.0BEEA40E61E3D14D83B7838979EAAE191AF0930 0.cert.pem

smtpd_tls_ciphers = medium

smtpd_tls_exclude_ciphers = SSLv2, aNULL, ADH, eNULL

smtpd_tls_key_file = /etc/certificates/Alains-Mac-mini.local.0BEEA40E61E3D14D83B7838979EAAE191AF0930 0.key.pem

smtpd_use_pw_server = yes

smtpd_use_tls = yes

tls_random_source = dev:/dev/urandom

unknown_local_recipient_reject_code = 550

use_sacl_cache = yes

virtual_alias_domains = $virtual_alias_maps hash:/Library/Server/Mail/Config/postfix/virtual_domains

virtual_alias_maps = hash:/etc/postfix/virtual