authentication : The Perl module Authen::OATH needed for two-factor authentication is not installed. Use the Perl Modules page in Webmin to install it.
Y al intentar acceder a Perl Modules para solucionar, aparece error 404 File not found
Es necesario instalar lo siguiente y después reiniciar el núcleo de webmin o toda la pc.
apt install -y gcc perl libany-moose-perl libdigest-hmac-perl perl-depends libauthen-oath-perl
perl -MCPAN -e "install Test::Moose"
perl -MCPAN -e "install Types::Standard"
perl -MCPAN -e "install Moo"
perl -MCPAN -e "install Authen::OATH