bitcoin-cli "Could not connect to the server" Brand new Raspberry Pi mainnet node following this walkthrough:

https://medium.com/@meeDamian/bitcoin-full-node-on-rbp3-revised-88bb7c8ef1d1

When I run this command:

bitcoin-cli -rpcuser=username -rpcpassword=password -rpcport=8332 getblockchaininfo

I receive the error:

error: Could not connect to the server 127.0.0.1:8332

When I tail debug.log, the node appears to be fully sync'd and picking up new blocks

My bitcoin.conf file is:

#is required for Fail2Ban
logips=1

#magic RBP optimizations
maxconnections=40
maxuploadtarget=5000

upnp=1

server=1
rpcuser='username'
rpcpassword='password'
rpcport='8332'

walletrbf=1

My apologies if my formatting is bad here, couldn't figure out how to get the .conf to paste as a block of text. Thank you for any ideas on what I'm doing wrong!
I encountered this error message when I have not started bitcoind.exe.
Starting bitcoind.exe solved the problem.