Any idea please?

Is the sender a "no-reply@...." address?

Hi Christian,

yes, exactly, when sending the auto reply to whatever email, in the mail header, I can see that the return path is empty like this:

"Return-Path: <"<>"@mydomain.com>"
Received: (qmail 30999 invoked by uid 5001); 29 Mar 2016 06:50:08 -0000
X-Sieve: Pigeonhole Sieve 0.2.2

Then some emails accept the auto reply but around 50% of email servers do not accept the auto reply from sogo and then I receive on my postmaster@ email a failure notice.
For example, Gmail's account do not accept the sogo auto reply.

thank you for your help

Return-Path should then be "<>" only, no @mydomain.com!
Do you have set an option to add that in your SMTP server?

Hi,

The return path is always written as:

Return-Path: <"<>"@mydomain.com>

I can't understand why, I didn't have set anything, where should I look into my SMTP server ?
Is any option in Sogo conf to set ?

Thank you

This depends on your SMTP server.
Which one are you using?
postfix, sendmail, exim or another one?

In sogo.conf there is only a way to set the used smtp server or smtp send command:
SOGoMailingMechanism, SOGoSMTPServer, WOSendMail + (SOGoSMTPAuthenticationType, SOGoForceExternalLoginWithEmail)

Hi,

Regarding the SMTP Server, QMAIL is used through SME Server (https://wiki.contribs.org/Main_Page)

Please have a look on my sogo.conf:

[root@mail ~]# cat /etc/sogo/sogo.conf

{
OCSFolderInfoURL = "mysql://sogo:XXXXXXXXXXXX@localhost/sogo/sogo_folder_info";
OCSSessionsFolderURL = "mysql://sogo:XXXXXXXXXXXX@localhost/sogo/sogo_sessions_folder";
SOGoProfileURL = "mysql://sogo:XXXXXXXXXXXX@localhost/sogo/sogo_user_profile";
OCSEMailAlarmsFolderURL = "mysql://sogo:XXXXXXXXXXXX@localhost/sogo/sogo_alarms_folder";

    SOGoACLsSendEMailNotifications = NO;
    SOGoAppointmentSendEMailNotifications = YES;
    SOGoAppointmentSendEMailReceipts = YES;
    SOGoEnableEMailAlarms = no;
    SOGoAuthenticationMethod = LDAP;
    SOGoFoldersSendEMailNotifications = NO;

            SOGoMailSpoolPath = "/var/spool/sogo";
    SOGoIMAPServer = "imap://localhost:143";
    SOGoMailDomain = MYDOMAIN.COM;
    SOGoMailingMechanism = smtp;
    SOGoSMTPServer = localhost;
    SOGoMailListViewColumnsOrder = (
        Flagged, Attachment, Subject, From, Unread, Date, Size
    );
    SOGoTrashFolderName = Trash;
    SOGoDraftsFolderName = Drafts;
    SOGoSentFolderName = Sent;

    SOGoSuperUsernames = (
        admin
    );
    SOGoTimeZone = Europe/Athens;
    WOWorkersCount = 3;

    SOGoMailAuxiliaryUserAccountsEnabled = NO;
    SOGoEnablePublicAccess = NO;

    SOGoMailCustomFromEnabled = YES;

    SOGoRefreshViewCheck = "every_10_minutes";
    SOGoFirstDayOfWeek = "1";
    SOGoFirstWeekOfYear = "First4DayWeek";
    SOGoCalendarDefaultReminder = "-PT15M";

    SOGoSieveServer = "sieve://localhost:4190";
    SOGoVacationEnabled = YES;
    SOGoForwardEnabled = YES;
    SOGoSieveScriptsEnabled = YES;
    NGImap4ConnectionStringSeparator = ".";

    SOGoUserSources = (

        {
            CNFieldName = cn;
            IDFieldName = uid;
            UIDFieldName = uid;
            baseDN = "ou=Users,dc=MYDOMAIN,dc=COM";
            bindFields = (uid);
            canAuthenticate = YES;
            displayName = "Users";
            hostname = localhost;
            id = users;
            isAddressBook = YES;
            port = 389;
            type = ldap;
        },
        {
            CNFieldName = cn;
            IDFieldName = cn;
            UIDFieldName = cn;
            baseDN = "ou=Groups,dc=MYDOMAIN,dc=COM";
            bindFields = (cn);
            canAuthenticate = YES;
            displayName = "Groups";
            hostname = localhost;
            id = groups;
            isAddressBook = YES;
            port = 389;
            type = ldap;
        }
    );

    NGUseUTF8AsURLEncoding = YES;
    WOMessageUseUTF8 = YES;
    WOParsersUseUTF8 = YES;
    WOPort = 127.0.0.1:20000;
    WOUseRelativeURLs = YES;

    SOGoMemcachedHost = 127.0.0.1;

   SOGoMailDomain = MYDOMAIN.COM;
   SOGoMailingMechanism = smtp;
   SOGoSMTPServer = localhost;

Those settings state you use the local SMTP server without going via any script.

I do not know qmail, sorry.
You should check its configuration.
Something like "allowing email addresses without domain part".

Thank you for your help.
I will inform you if I resolve it.

Not related to SOGo.

Finally I resolved it.

I was due to QMAIL which was returning "null sender" from the auto-reply message.

https://bugs.contribs.org/show_bug.cgi?id=9883

I resolved it with updating QMAIL package.

thanks,
G.