Install Status Node on Arch Linux: No 'docker' in your $PATH

I’m following the steps to install a Status Node on Arch Linux.

But when I get to Step 5: make run-mailserver-docker, I receive this error message:

[email protected] status-go]$ make run-mailserver-docker
make[1]: Entering directory '/home/user/status-go/_assets/compose/mailserver'
make[1]: which: No such file or directory
make[1]: which: No such file or directory
make[1]: which: No such file or directory
Makefile:41: ** No 'docker' in your $PATH. Please install it.**  Stop.
make[1]: Leaving directory '/home/user/status-go/_assets/compose/mailserver'
make: *** [Makefile:354: run-mailserver-docker] Error 2

Docker appears to be installed:

$ docker --version
Docker version 20.10.10, build b485636f4b

$ docker-compose --version
docker-compose version 1.26.2, build eefe0d31

$ sudo systemctl status docker
● docker.service - Docker Application Container Engine
     Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor pr>
     Active: active (running) 

What step am I missing?