Unable to install Pi-hole (curl error)

I SSH'd into my pihole and entered the command as shows, only to receive:

-bash: -sSL: command not found

Any idea what I'm doing wrong?

What is the output of curl --version?

curl 7.38.0 (arm-unknown-linux-gnueabihf) libcurl/7.38.0 OpenSSL/1.0.1t zlib/1.2.8 libidn/1.29 libssh2/1.4.3 librtmp/2.3

Did you enter this exact command?

curl -sSL https://install.pi-hole.net | bash