Yahoo rejecting mail and error Message Header not RFC compliant 291

I'm on ISPCONFIG 3.0.5 Center 6.5., Mails I sent to yahoo is rejected with error Message Header not RFC compliant 291.
I know this double message headers issue was fixed in 3.1 but is there a work around for 3.0.5 I'm wary about upgrading to 3.1at this time. I'm using courier instead of dovecot on ISPCONFIG 3.0.5 will I get any problems if I upgrade to 3.1

 

I highly discourage using 3.0.5 since it already receives no updates for a long time – even security-related ones.
That said I fear there is no easy way using patches from 3.1. Do you mean mails that you send by hand? The Patch in 3.1 was only related to mails being sent directly from inside ISPConfig (e. g. quota warning).

 

Yes, double Headers on mail I send to yahoo email addresses

 

That's not an answer to my question
Does it occur when you send Mails from your mail client on your computer or does it occur on mails sent by ISPConfig, e.g. quota warnings?

 

For now only on mails sent from mail client on my computer. From my investigation it started when I created a second domain on ISPCONFIG with a separate Ipv4 address

 

That does not sound like being related to ISPConfig. The bug you mentioned that was fixed only affected mails sent by the ISPConfig system, not those sent by mail clients, as far as I know.
Have you investigated, which header exactly is doubled?

 

The TO field is double

 

What mail client are you using and have you set something like "send (outgoing) copy to" or an additional external forwarding for your mail address?

 

Not at all

 

Have you tried sending via webmailer (roundcube / squirrelmail) if it occurs there, too?

 

yes same double header

 

Please post the contents of your /etc/postfix/main.cf (domains anonymized if needed).

 

Contents of /etc/postfix/main.cf

Code:

readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
virtual_alias_domains =
virtual_alias_maps = hash:/etc/mailman/virtual-mailman, proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf, proxy:mysql:/etc/postfix/mysql-virtual_email2email.cf
virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains.cf
virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf
virtual_mailbox_base = /var/vmail
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000
smtpd_sasl_auth_enable = yes
broken_sasl_auth_clients = yes
smtpd_sasl_authenticated_header = yes
smtpd_recipient_restrictions = reject_authenticated_sender_login_mismatch, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination,
            reject_invalid_hostname,
            reject_non_fqdn_hostname,
            reject_non_fqdn_sender,
            reject_unknown_sender_domain,
            reject_unknown_recipient_domain,
            reject_maps_rbl,
            check_relay_domains,
check_recipient_access mysql:/etc/postfix/mysql-virtual_recipient.cf
smtpd_use_tls = yes
smtpd_tls_security_level = may
smtpd_tls_CAfile = /etc/letsencrypt/live/xxxxxxxxxxx.com/chain.pem

smtpd_tls_cert_file = /etc/postfix/smtpd.cert
smtpd_tls_key_file = /etc/postfix/smtpd.key


transport_maps = hash:/var/lib/mailman/data/transport-mailman, proxy:mysql:/etc/postfix/mysql-virtual_transports.cf
relay_domains = mysql:/etc/postfix/mysql-virtual_relaydomains.cf
relay_recipient_maps = mysql:/etc/postfix/mysql-virtual_relayrecipientmaps.cf
proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $smtpd_sender_login_maps
smtpd_sender_restrictions =check_sender_access mysql:/etc/postfix/mysql-virtual_sender.cf, reject_unknown_sender_domain, reject_unlisted_sender, reject_sender_login_mismatch
smtpd_client_restrictions = check_client_access mysql:/etc/postfix/mysql-virtual_client.cf
smtpd_client_message_rate_limit = 100
maildrop_destination_concurrency_limit = 1
maildrop_destination_recipient_limit = 1
virtual_transport = maildrop
header_checks = regexp:/etc/postfix/header_checks
mime_header_checks = regexp:/etc/postfix/mime_header_checks
nested_header_checks = regexp:/etc/postfix/nested_header_checks
body_checks = regexp:/etc/postfix/body_checks
smtp_tls_security_level = may
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
smtpd_tls_protocols = !SSLv2,!SSLv3
smtp_tls_protocols = !SSLv2,!SSLv3
myhostname = server.xxxxxxxxxxx.com
mynetworks = 127.0.0.0/8 [::1]/128 xxx.xxx.45.124 xxx.xxx.233.104
content_filter = amavis:[127.0.0.1]:10024
receive_override_options = no_address_mappings

smtpd_milters           = inet:127.0.0.1:8891
non_smtpd_milters       = $smtpd_milters
milter_default_action   = accept
milter_protocol         = 2
message_size_limit = 0
relayhost =
mailbox_size_limit = 0

smtpd_helo_required = yes
disable_vrfy_command = yes
strict_rfc821_envelopes = yes
invalid_hostname_reject_code = 554
multi_recipient_bounce_reject_code = 554
non_fqdn_reject_code = 554
relay_domains_reject_code = 554
unknown_address_reject_code = 554
unknown_client_reject_code = 554
unknown_hostname_reject_code = 554
unknown_local_recipient_reject_code = 554
unknown_relay_recipient_reject_code = 554
unknown_sender_reject_code = 554
unknown_virtual_alias_reject_code = 554
unknown_virtual_mailbox_reject_code = 554
unverified_recipient_reject_code = 554
unverified_sender_reject_code = 554

maps_rbl_domains =
            dsn.rfc-ignorant.org,
            dul.dnsbl.sorbs.net,
            list.dsbl.org,
            sbl-xbl.spamhaus.org,
            bl.spamcop.net,
            dnsbl.sorbs.net,
            cbl.abuseat.org,
            ix.dnsbl.manitu.net,
            combined.rbl.msrbl.net,
            rabl.nuclearelephant.com

smtpd_sender_login_maps = proxy:mysql:/etc/postfix/mysql-virtual_sender_login_maps.cf

Thanks