在Ruby on Rails - Heroku 部署上，我得到了一个错误heroku[route]: at=error code=H10 desc="App crashed" method经过一些调试日志文本，我得到的日志文件的主要部分：
2022-01-08T11:12:12.754916+00:00 heroku[web.1]: Starting process with command `bin/rails server -p ${PORT:-5000} -e production`
2022-01-08T11:12:16.534794+00:00 app[web.1]: => Booting Puma
2022-01-08T11:12:16.534809+00:00 app[web.1]: => Rails 6.1.4.4 application starting in production
2022-01-08T11:12:16.534810+00:00 app[web.1]: => Run `bin/rails server --help` for more startup options
2022-01-08T11:12:17.742438+00:00 app[web.1]: Exiting
2022-01-08T11:12:17.745593+00:00 app[web.1]: /app/vendor/bundle/ruby/3.1.0/gems/bootsnap-1.9.3/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:34:in `require': cannot load such file -- net/pop (LoadError)
2022-01-08T11:12:17.745616+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/zeitwerk-2.5.3/lib/zeitwerk/kernel.rb:35:in `require'
2022-01-08T11:12:17.745630+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail/network/retriever_methods/pop3.rb:36:in `<class:POP3>'
2022-01-08T11:12:17.745642+00:00 app[web.1]: from /app/vendor/bundle/ruby/3.1.0/gems/mail-2.7.1/lib/mail/network/retriever_methods/pop3.rb:35:in …