When you open the tab "Mail" on "Server Config" and try to open another tab, even without change anything on the form, shows the error message "1. Uid-mapping cannot be changed if there are already mail users.". I noticed that the "mailbox_virtual_uidgid_maps" (validate_server_mail_config class) function looks up the server settings where ISPConfig is (when comparing the information between what is saved and the form), not the server selected in the server list.
Having the exact same problem (ISPConfig 3.1.7p1). Opened another tab and got the same error. Also all mail settings were gone. Checked the database and all entries in the mail_user table were still correct. Mail is still working. But settings in Server Config / Mail are all empty and cannot be re-entered. Has this issue ever been resolved. Is there a way to fix it?
The problem happens when the main system config in corrupted. This happens e,g, when you open the server table in phpmyadmin and click on a row so that phpmyadmin opens it's inline editor.PHPMyAdmin then corrupts the table even if you don't save changes by removing linebreaks from the system config. To solve the issue, open the record of this server in the server table in ISPConfig with phpmyadmin (use the normal edit mode and not the inlinde data editor!) and paste this into the config field: Code: [global] webserver=apache mailserver=postfix dnsserver=mydns [server] auto_network_configuration=n ip_address=0.0.0.0 netmask=255.255.255.0 v6_prefix= gateway=0.0.0.0 hostname=server1.domain.tld nameservers=8.8.8.8,8.8.4.4 firewall=bastille loglevel=2 admin_notify_events=1 backup_dir=/var/backup backup_dir_is_mount=n backup_mode=rootgz backup_time=0:00 backup_delete=n monit_url= monit_user= monit_password= munin_url= munin_user= munin_password= monitor_system_updates=y migration_mode=n [mail] module=postfix_mysql maildir_path=/var/vmail/[domain]/[localpart] homedir_path=/var/vmail maildir_format=maildir dkim_path=/var/lib/amavis/dkim dkim_strength=1024 pop3_imap_daemon=courier mail_filter_syntax=maildrop mailuser_uid=5000 mailuser_gid=5000 mailuser_name=vmail mailuser_group=vmail mailbox_virtual_uidgid_maps=n relayhost= relayhost_user= relayhost_password= mailbox_size_limit=0 message_size_limit=0 mailbox_quota_stats=y realtime_blackhole_list=zen.spamhaus.org overquota_notify_admin=y overquota_notify_client=y overquota_notify_freq=7 overquota_notify_onok=n sendmail_path=/usr/sbin/sendmail [getmail] getmail_config_dir=/etc/getmail [web] server_type=apache website_basedir=/var/www website_path=/var/www/clients/client[client_id]/web[website_id] website_symlinks=/var/www/[website_domain]/:/var/www/clients/client[client_id]/[website_domain]/ website_symlinks_rel=n network_filesystem=n vhost_conf_dir=/etc/apache2/sites-available vhost_conf_enabled_dir=/etc/apache2/sites-enabled nginx_vhost_conf_dir=/etc/nginx/sites-available nginx_vhost_conf_enabled_dir=/etc/nginx/sites-enabled security_level=20 user=www-data group=www-data nginx_user=www-data nginx_group=www-data apps_vhost_enabled=y apps_vhost_port=8081 apps_vhost_ip=_default_ apps_vhost_servername= php_open_basedir=[website_path]/web:[website_path]/private:[website_path]/tmp:/var/www/[website_domain]/web:/srv/www/[website_domain]/web:/usr/share/php5:/usr/share/php:/tmp:/usr/share/phpmyadmin:/etc/phpmyadmin:/var/lib/phpmyadmin:/dev/random:/dev/urandom htaccess_allow_override=All awstats_conf_dir=/etc/awstats awstats_data_dir=/var/lib/awstats awstats_pl=/usr/lib/cgi-bin/awstats.pl awstats_buildstaticpages_pl=/usr/share/awstats/tools/awstats_buildstaticpages.pl php_ini_path_apache=/etc/php5/apache2/php.ini php_ini_path_cgi=/etc/php5/cgi/php.ini check_apache_config=y enable_sni=y enable_spdy=n skip_le_check=n enable_ip_wildcard=y overtraffic_notify_admin=y overtraffic_notify_client=y nginx_cgi_socket=/var/run/fcgiwrap.socket php_fpm_init_script=php5-fpm php_fpm_ini_path=/etc/php5/fpm/php.ini php_fpm_pool_dir=/etc/php5/fpm/pool.d php_fpm_start_port=9010 php_fpm_socket_dir=/var/lib/php5-fpm set_folder_permissions_on_update=n add_web_users_to_sshusers_group=y connect_userid_to_webid=n connect_userid_to_webid_start=10000 web_folder_protection=y php_ini_check_minutes=1 overquota_notify_admin=y overquota_notify_client=y overquota_notify_freq=7 overquota_db_notify_admin=y overquota_db_notify_client=y overquota_notify_onok=n [dns] bind_user=root bind_group=bind bind_zonefiles_dir=/etc/bind named_conf_path=/etc/bind/named.conf named_conf_local_path=/etc/bind/named.conf.local disable_bind_log=n [fastcgi] fastcgi_starter_path=/var/www/php-fcgi-scripts/[system_user]/ fastcgi_starter_script=.php-fcgi-starter fastcgi_alias=/php/ fastcgi_phpini_path=/etc/php5/cgi/ fastcgi_children=8 fastcgi_max_requests=5000 fastcgi_bin=/usr/bin/php-cgi fastcgi_config_syntax=2 [jailkit] jailkit_chroot_home=/home/[username] jailkit_chroot_app_sections=basicshell editors extendedshell netutils ssh sftp scp groups jk_lsh jailkit_chroot_app_programs=/usr/bin/groups /usr/bin/id /usr/bin/dircolors /usr/bin/lesspipe /usr/bin/basename /usr/bin/dirname /usr/bin/nano /usr/bin/pico /usr/bin/mysql /usr/bin/mysqldump /usr/bin/git /usr/bin/git-receive-pack /usr/bin/git-upload-pack /usr/bin/unzip /usr/bin/zip /bin/tar /bin/rm /usr/bin/patch /usr/bin/which /usr/lib/x86_64-linux-gnu/libmemcached.so.11 /usr/lib/x86_64-linux-gnu/libmemcachedutil.so.2 /usr/lib/x86_64-linux-gnu/libMagickWand-6.Q16.so.2 /opt/php-5.6.8/bin/php /opt/php-5.6.8/include /opt/php-5.6.8/lib jailkit_chroot_cron_programs=/usr/bin/php /usr/bin/perl /usr/share/perl /usr/share/php [vlogger] config_dir=/etc [cron] init_script=cron crontab_dir=/etc/cron.d wget=/usr/bin/wget [rescue] try_rescue=n do_not_try_rescue_httpd=n do_not_try_rescue_mysql=n do_not_try_rescue_mail=n [xmpp] xmpp_use_ispv6=n xmpp_bosh_max_inactivity=30 [email protected], [email protected] xmpp_modules_enabled=saslauth, tls, dialback, disco, discoitems, version, uptime, time, ping, admin_adhoc, admin_telnet, bosh, posix, announce, offline, webpresence, mam, stream_management, message_carbons xmpp_port_http=5290 xmpp_port_https=5291 xmpp_port_pastebin=5292 xmpp_port_bosh=5280 It might be that you have to adjust some fields under ISPConfig Sysetm > Server config
