error redis connection to 127.0 0.1 6379 failed just in pm2 code example

Example 1: Error: Redis connection to 127.0.0.1:6379 failed - connect ECONNREFUSED 127.0.0.1:6379

sudo service redis-server status

Example 2: Error: Redis connection to 127.0.0.1:6379 failed - connect ECONNREFUSED 127.0.0.1:6379

sudo apt-get install redis-server