Before you can use TFA in Webmin/Virtualmin you must install Authen::OATH. And before that you need to install Perl-CPAN first.

Here's how:

1. yum -y install perl-CPAN

2. perl -MCPAN -e "install Test::Moose"

3. perl -MCPAN -e "install Types::Standard"
   

4. perl -MCPAN -e "install Moo"

5. perl -MCPAN -e "install Authen::OATH"

 And now you can activate TFA like Google Authenticator in your server.