[RESOLVED] Problem from new install Perfect server

Hi,
After probleme with migrate to new PHP. I want to prepare new server with last new configuration (https://www.howtoforge.com/tutorial...-stretch-apache-bind-dovecot-ispconfig-3-1/2/), but at : "apt-get install mailman" I have this two times
"Traceback (most recent call last):
File "/var/lib/mailman/bin/list_lists", line 50, in <module>
from Mailman import MailList
File "/var/lib/mailman/Mailman/MailList.py", line 51, in <module>
from Mailman.Archiver import Archiver
File "/var/lib/mailman/Mailman/Archiver/__init__.py", line 17, in <module>
from Archiver import *
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 37, in <module>
from Mailman.i18n import _
File "/var/lib/mailman/Mailman/i18n.py", line 37, in <module>
_ctype_charset = _get_ctype_charset()
File "/var/lib/mailman/Mailman/i18n.py", line 31, in _get_ctype_charset
old = locale.setlocale(locale.LC_CTYPE, '')
File "/usr/lib/python2.7/locale.py", line 581, in setlocale
return _setlocale(category, locale)
locale.Error: unsupported locale setting"
And end with "
dpkg: error processing package mailman (--configure):
subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
mailman
E: Sub-process /usr/bin/dpkg returned an error code (1)
"
I found this on web : https://askubuntu.com/questions/665830/error-updating-mailman
But nothing, the problem presists.
Cordialy


EDIT : Repair with this :

1. dpkg-reconfigure locales
2. cd /var/lib/dpkg/info/
   rm mailman*
   apt-get clean all
   apt-get update
   apt-get upgrade
3. apt-get install mailman