==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
Ubuntu 18.04.6 LTS (GNU/Linux 4.15.0-112-generic x86_64)
root@mail:~/iRedMail-0.9.9$ sudo bash iRedMail.sh
'universe' distribution component is already enabled for all sources.
[ INFO ] Checking configuration file: /home/srvadmin/iRedMail-0.9.9/config ... [FOUND]
< Question > Use it for mail server setting? [y|N]y
[ INFO ] Use config file: /home/srvadmin/iRedMail-0.9.9/config for mail server setting.
[ INFO ] Import installation process status from file: /home/srvadmin/iRedMail-0.9.9/runtime/install.status.
[ INFO ] Add apt repo for SOGo: packages.inverse.ca
[ INFO ] Import apt key (0x810273C4) for SOGo repo (packages.inverse.ca).
Executing: /tmp/apt-key-gpghome.o1dfCbo1Lr/gpg.1.sh --keyserver keyserver.ubuntu.com --recv-key 0x810273C4
gpg: key 19CDA6A9810273C4: "Inverse Support (package signing) <support@inverse.ca>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
[ INFO ] Resynchronizing the package index files (apt-get update) ...
Hit:1 security.ubuntu.com/ubuntu bionic-security InRelease
Hit:3 archive.ubuntu.com/ubuntu bionic InRelease                                                                         
Hit:4 archive.ubuntu.com/ubuntu bionic-updates InRelease                                   
Hit:5 archive.ubuntu.com/ubuntu bionic-backports InRelease                                 
Ign:2 packages.sogo.nu/nightly/4/ubuntubionic InRelease
Err:6 packages.sogo.nu/nightly/4/ubuntu bionic Release
  404  Not Found [IP: 31.172.161.89 443]
Reading package lists... Done
E: The repository 'packages.inverse.ca/SOGo/nightly/4/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
[ INFO ] Installing package(s): postfix postfix-pcre libsasl2-modules mariadb-client mariadb-server postfix-mysql libdbd-mysql-perl php-cli php-fpm php-json php-gd php-curl mcrypt php-intl php-xml php-mbstring php-mysql nginx-full dovecot-imapd dovecot-pop3d dovecot-lmtpd dovecot-managesieved dovecot-sieve dovecot-mysql amavisd-new libcrypt-openssl-rsa-perl libmail-dkim-perl clamav-freshclam clamav-daemon spamassassin altermime arj nomarch cpio lzop cabextract p7zip-full rpm ripole libmail-spf-perl unrar-free pax lrzip mlmmj sogo sogo-activesync sope4.9-gdl1-mysql python-sqlalchemy python-dnspython python-mysqldb python-pymysql python-jinja2 python-netifaces python-webpy python-beautifulsoup python-lxml python-pycurl python-requests uwsgi uwsgi-plugin-python python-bcrypt fail2ban zlib1g libuuid1 libmnl0 curl lm-sensors netcat bzip2 acl patch cron tofrodos logwatch unzip bsdutils liblz4-tool
Reading package lists...
Building dependency tree...
Reading state information...
E: Unable to locate package sogo-activesync
E: Unable to locate package sope4.9-gdl1-mysql
E: Couldn't find any package by glob 'sope4.9-gdl1-mysql'
E: Couldn't find any package by regex 'sope4.9-gdl1-mysql'
<< 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: forum.iredmail.org
====

Hello! I am using the mail server version 0.9.9 on Ubuntu 18.04. I am trying to move to a new server. I installed the same distribution, made copies of the database and settings, but I cannot get the repository
Ign:2 packages.sogo.nu/nightly/4/ubuntu bionic InRelease
Err:6 packages.sogo.nu/nightly/4/ubuntu bionic Release

What is the best way to solve this situation? Replace the link to another sogo package in (/etc/apt/sources.list)? Will it be compatible? Or take the sogo package from the old server somehow?

Found on the site sogo.nu/support/faq/how-to-install-nightly-sogo-versions-on-ubuntu.html

"Ubuntu 18.04 (Bionic Beaver)
deb packages.sogo.nu/nightly/5/ubuntu/ bionic bionic"