Why have I got the «PHP Fatal error: Uncaught Magento\Framework\Exception\LocalizedException: Area code is not set» failure?

Great thanks!
I am seeing this error in the latest version…

PHP Fatal error:  Uncaught Magento\Framework\Exception\LocalizedException: Area code is not set in /vendor/magento/framework/App/State.php:139

This error is not related to the Stripe payment extension.
I can solve such problems on the terms of my generic Magento 2 support service.

2 posts were split to a new topic: How can I fix the «TypeError: require.toUrl is not a function» issue?