Move Magento 2 Area code is not set problem

Question

I am trying to move magento 2 to another server but when I am trying to flush cache I am getting this error:

php bin/magento cache:flush

[Magento\Framework\Exception\SessionException]
Area code not set: Area code must be set before starting a session.

[Magento\Framework\Exception\LocalizedException]
Area code is not set

cache:flush [--bootstrap="..."] [types1] ... [typesN]

I already updated database with the new directory.

What should I do ?