Send customer email to check if email is working on server
Create ~/.n98-magerun/modules/ if it doesn't already exist.
mkdir -p ~/.n98-magerun2/modules/
Clone the magerun-addons repository in there
cd ~/.n98-magerun2/modules/ && git clone https://github.com/djfordz/magerun2-addons.git df-addons2
Run Command
n98-magerun2 customer:sendemail