Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires backstage/laravel-mails v3.0.13 (exact version match), it is satisfiable by backstage/laravel-mails[v3.0.13] from composer repo (https://repo.packagist.org) but backstage/laravel-mails[dev-feature/rename-filament-mails-to-mails, ..., dev-pullrequests/Skullbock/feature/aws-ses-driver, v1.0.0, ..., v1.4.4, v2.0.0-beta33, ..., 2.x-dev, v3.0.0, ..., v3.0.12] from vcs repo (github git@github.com:backstagephp/laravel-mails.git) has higher repository priority. The packages from the higher priority repository do not match your constraint and are therefore not installable. That repository is canonical so the lower priority repo's packages are not installable. See https://getcomposer.org/repoprio for details and assistance.