Most probably CPANTS databases are being regenerated from scratch due to major changes in Kwalitee metrics or updates of relevant modules/perl. Usually this maintenance takes about a day or two, and some of the information may be old or missing tentatively. Sorry for the inconvenience.
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: License 'gpl3' is invalid (license) [Validation: 1.4]
Add a META.json to the distribution. Your buildtool should be able to autogenerate it.
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.
| Name | Abstract | Version | View |
|---|---|---|---|
| App::EUMM::Upgrade | Perl tool to upgrade ExtUtils::MakeMaker-based Makefile.PL | 0.21 | metacpan |