After you install Magento 2, you will see “One or more indexers are invalid. Make sure your Magento cron job is running” on the Magento 2 backend.
In fact, it’s only a reindex problem, which Magento 1 is very easily to reindex on backend but we could use Magento CLI to reindex for Magento 2. Now Web Dux will show you how to fix “One or more indexers are invalid. Make sure your Magento cron job is running” by Magento CLI.
Please go to the root folder of your magento 2 installation and run the below command :
php bin/magento indexer:reindex
That’s all, so you can go to your Magento 2 backend and check if it’s ok.