Take a look at the META.yml Spec at https://metacpan.org/pod/CPAN::Meta::History::Meta_1_4 (for version 1.4) or https://metacpan.org/pod/CPAN::Meta::Spec (for version 2), and change your META.yml accordingly.
Error: Expected a list structure (author) [Validation: 1.3]
Add 'use strict' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules are strictly written.
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
Add 'use warnings' (or its equivalents) to all modules, or convince us that your favorite module is well-known enough and people can easily see the modules warn when something bad happens.
Error: Encode::HanExtra, Encode::TW::Unisys::SOSI1, Encode::TW::Unisys::SOSI2
Split the distribution, or fix the version numbers to make them consistent (use the highest version number to avoid version downgrade).
Add a 'repository' resource to the META.yml via 'meta_add' accessor (for Module::Build) or META_ADD parameter (for ExtUtils::MakeMaker).
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.