I’ve just failed to install GPL version on Ubuntu 18.0.4.
- Create new droplet from Digital Ocean (template Ubuntu 18.04 LTS)
apt dist-upgrade -y to make sure the system is up to date.
- Run the install.sh file (follow the guide on website)
The error is printed (my domain & IP is masked)
root@s2:~# ./install.sh -n s2.mydomain.com -m -f
2020-05-22 09:10:57 URL:https://software.virtualmin.com/lib/slib.sh [22146/22146] -> "slib.sh" 
[INFO] Started installation log in /root/virtualmin-install.log
▣□□ Phase 1 of 3: Setup
Downloading RPM-GPG-KEY-virtualmin-6 [ ✔ ]
Downloading RPM-GPG-KEY-webmin [ ✔ ]
Installing Virtualmin 6 key [ ✔ ]
Installing Webmin key [ ✔ ]
Updating apt metadata [ ✔ ]
Downloading repository metadata [ ✔ ]
Enabling universe repositories, if not already available [ ✔ ]
Disabling cdrom: repositories [ ✔ ]
Cleaning out old metadata [ ✔ ]
▣▣□ Phase 2 of 3: Installation
Installing Webmin [ ✔ ]
Installing Usermin [ ✔ ]
Installing fail2ban [ ✔ ]
Removing nginx (if installed) before LAMP installation. [ ✔ ]
Removing unneeded packages that could confict with LAMP stack. [ ✔ ]
Installing postfix [ ✔ ]
Installing virtualmin-lamp-stack-minimal [ ✔ ]
Installing Virtualmin and plugins [ ✔ ]
22 May 09:15:31 ntpdate: adjust time server 220.127.116.11 offset 0.017881 sec
Installing updates to Virtualmin-related packages [ ✔ ]
▣▣▣ Phase 3 of 3: Configuration
Can't locate Virtualmin/Config.pm in @INC (you may need to install the Virtualmin::Config module) (@INC contains: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.26.1 /usr/local/share/perl/5.26.1 /usr/lib/x86_64-linux-gnu/perl5/5.26 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl/5.26 /usr/share/perl/5.26 /usr/local/lib/site_perl /usr/lib/x86_64-linux-gnu/perl-base) at /usr/bin/virtualmin-config-system line 9.
BEGIN failed--compilation aborted at /usr/bin/virtualmin-config-system line 9.
▣▣▣ Cleaning up
[WARNING] The following errors occurred during installation:
◉ Postinstall configuration returned an error.
The file /root/virtualmin-install.log content: https://gist.github.com/trinhpham/cbf8302e1d76823ab4f06cf8bd34caba