Unhandled error event: Error: connect ECONNREFUSED

I'm using pm2 to ensure laravel-echo-server is running. Performing a pm2 logs 0 gives me some errors. I'm running the server on a Google Compute Engine Instance and have setup some firewall ingress rules.

0|echo-ser | ⚠ Starting server in DEV mode... 
0|echo-ser | 
0|echo-ser | ✔ Running at localhost on port 6001 
0|echo-ser | ✔ Channels are ready. 
0|echo-ser | ✔ Listening for http events... 
0|echo-ser | 
0|echo-ser | L A R A V E L E C H O S E R V E R 
0|echo-ser | 
0|echo-ser | version 1.5.0 
0|echo-ser | 
0|echo-ser | ⚠ Starting server in DEV mode... 
0|echo-ser | 
0|echo-ser | ✔ Running at localhost on port 6001 
0|echo-ser | ✔ Channels are ready. 
0|echo-ser | ✔ Listening for http events...

/root/.pm2/logs/echo-server-error.log last 15 lines: 
0|echo-ser | at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1191:14) 
0|echo-ser | [ioredis] Unhandled error event: Error: connect ECONNREFUSED 127.0.0.1:6379 

via Chebli Mohamed