Thank you...

But, I'm thinking a method interactive and manual (step by step)  to detect the problem...  Like telnet, etc, etc.

I found the problem...

I bit of history.

I was trying to install iredMail on CentOS 7

# mkdir iRedMail
# cd iRedMail
# wget    https://bitbucket.org/zhb/iredmail/downloads/iRedMail-0.9.6.tar.bz2
# tar xjf iRedMail-0.9.6.tar.bz2
# cd iRedMail-0.9.6
# bash iRedMail.sh

But I got this error.

ERROR...
    Package clamav-server is obsoleted by clamav, but obsoleting package does not provide for requirements
    ---> Package systemd-libs.x86_64 0:219-19.el7 will be updated
    --> Processing Dependency: systemd-libs = 219-19.el7 for package: libgudev1-219-19.el7.x86_64
    ---> Package systemd-libs.x86_64 0:219-30.el7_3.8 will be an update
    ---> Package systemd-python.x86_64 0:219-19.el7 will be updated
    ---> Package systemd-python.x86_64 0:219-30.el7_3.8 will be an update
    ---> Package systemd-sysv.x86_64 0:219-19.el7 will be updated
    ---> Package systemd-sysv.x86_64 0:219-30.el7_3.8 will be an update
    --> Running transaction check
    ---> Package clamav-server-systemd.noarch 0:0.99.2-1.el7 will be installed
    --> Processing Dependency: clamav-server = 0.99.2-1.el7 for package: clamav-server-systemd-0.99.2-1.el7.noarch
    Package clamav-server is obsoleted by clamav, but obsoleting package does not provide for requirements
    ---> Package libgudev1.x86_64 0:219-19.el7 will be updated
    ---> Package libgudev1.x86_64 0:219-30.el7_3.8 will be an update
    --> Finished Dependency Resolution
    Error: Package: clamav-server-systemd-0.99.2-1.el7.noarch (epel)
          Requires: clamav-server = 0.99.2-1.el7
          Installing: 1:clamav-0.98.4-65.el7.x86_64 (atrpms)
          clamav-server = 1:0.98.4-65.el7
          Available: clamav-server-0.99.2-1.el7.x86_64 (epel)
          clamav-server = 0.99.2-1.el7
          Available: clamav-0.99.2-1.el7.x86_64 (epel)
          Not found
    You could try using --skip-broken to work around the problem
    You could try running: rpm -Va --nofiles --nodigest
    << ERROR >> Installation failed, please check the terminal output.
    << ERROR >> If you're not sure what the problem is, try to get help in iRedMail
    << ERROR >> forum: http://www.iredmail.org/forum/
#

I was trying to solve with:

# yum install clamav clamav-data clamav-devel clamav-filesystem clamav-lib clamav-scanner clamav-scanner-systemd clamav-server clamav-server-systemd clamav-update

But I was experimenting the same ERROR.

Then removed previosly installed clamav*rpm packages and I installed from downloaded of specific source:

# wget    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-0.99.2-1.el7.x86_64.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-data-0.99.2-1.el7.noarch.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-devel-0.99.2-1.el7.x86_64.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-filesystem-0.99.2-1.el7.noarch.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-lib-0.99.2-1.el7.x86_64.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-scanner-0.99.2-1.el7.noarch.rpm http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-scanner-systemd-0.99.2-1.el7.noarch.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-server-0.99.2-1.el7.x86_64.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-server-systemd-0.99.2-1.el7.noarch.rpm    http://dl.fedoraproject.org/pub/epel/7/x86_64/c/clamav-update-0.99.2-1.el7.x86_64.rpm
# yum install *.rpm

All was installed without problem...

But, Running

bash iRedMail.sh

the problem again raise up.

I solve this editing the file

changing the line

ALL_PKGS="${ALL_PKGS} clamav clamav-update clamav-server clamav-server-systemd"

by:

ALL_PKGS="${ALL_PKGS} " #clamav clamav-update clamav-server clamav-server-systemd"

Later I remove all clamav*.rpm installed by iRedMail.sh and reinstalled the downloaded rpm again with

# yum install clamav*.rpm 

Again I face another problem!

file /usr/lib64/dovecot/libdovecot-sieve.so.0.0.0 conflicts between attempted installs of dovecot-pigeonhole-2:0.4.2-32.1.el7.x86_64 and dovecot-1:2.2.28-1.el7.centos.x86_64

I had similar solution, I remove all dovecot*.rpm  installed by iRedMail.sh and install rpm packages with another source:

# wget    ftp://195.220.108.108/linux/centos/7.3.1611/os/x86_64/Packages/dovecot-2.2.10-7.el7.x86_64.rpm    ftp://195.220.108.108/linux/centos/7.3.1611/os/x86_64/Packages/dovecot-pgsql-2.2.10-7.el7.x86_64.rpm    ftp://195.220.108.108/linux/centos/7.3.1611/os/x86_64/Packages/dovecot-mysql-2.2.10-7.el7.x86_64.rpm    ftp://195.220.108.108/linux/centos/7.3.1611/os/x86_64/Packages/dovecot-pigeonhole-2.2.10-7.el7.x86_64.rpm 
# yum install dovecot*.rpm

All rpm packages was installed without problem...

Now changing the lines on file

ALL_PKGS="${ALL_PKGS} dovecot dovecot-pigeonhole"
ALL_PKGS="${ALL_PKGS}  dovecot-mysql dovecot-pgsql"

by

ALL_PKGS="${ALL_PKGS} " # dovecot dovecot-pigeonhole"
ALL_PKGS="${ALL_PKGS} " # dovecot-mysql dovecot-pgsql"

I run again

# bash iRedMail.sh

without problem...

Maybe it's a problem of repo, but I solved in this manner.

The problem was previously I disabled sieve protocol into dovecot.conf  file. When I got :

doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: protocols: Unknown protocol: sieve.

Then I need to reinstall the server and reenabled the protocol again.