Postgres starting as root user on running system service

I have an application running on Ubuntu server that's using PostgreSQL.

I can run the application's executable (as a non-root user) from the project's directory.

I have created a service for this application (/etc/systemd/system/cineapi.service), so that it starts automatically on reboot. The contents of this file are:

[Unit]Description=cineapi[Service]Type=simpleRestart=on-failureRestartSec=5sWorkingDirectory=/home/saurabh/projects/cineapiExecStart=/home/saurabh/projects/cineapi/cineapi.o[Install]WantedBy=multi-user.target

When a reload the system daemon and start the service like:

sudo systemctl daemon-reloadsudo service cineapi start

I'm getting an error:

pq: password authentication failed for user "root"

I dont understand why this is happening. I'm not using the "root" user anywhere in the application. It's .env file looks like

postgres://goapi:somepassword@MY_IPV4_ADDR:DB_PORT/cineapi

and is sourced at startup. I also have the following changes in:

• /etc/postgresql/16/main/postgresql.conf

  password_encryption = scram-sha-256

• /etc/postgresql/16/main/pg_hba.conf

  host    cineapi         goapi           MY_IPV4_ADDR            scram-sha-256