Can't start or update ghost -- ghost_undefined

Hello, I can’t start nor update ghost any longer. It seems ghost-cli don’t recognize that I actually have a specific instance defined, called my-blog-com … but it refers to ghost_undefined. I have installed ghost several months ago and am running it directly/locally, not through docker. How can I solve this?

My blog does start stop if I use sudo systemctl start ghost_my-blog-com whose content is the following:

[Unit]
Description=Ghost systemd service for blog: my-blog-com
Documentation=https://docs.ghost.org
Requires=var.mount

[Service]
Type=simple
WorkingDirectory=/var/www/blog
User=1002
Environment="NODE_ENV=production"
ExecStart=/usr/local/n/bin/node /usr/local/npm/bin/ghost run
Restart=always

[Install]
WantedBy=multi-user.target

Here’s what I get when I try ghost start. Similar thing with ghost update

nodeghost@myserver:/var/www/blog$ ghost start
+ sudo systemctl is-active ghost_undefined
✔ Checking system Node.js version - found v14.17.0
✔ Ensuring user is not logged in as ghost user
✔ Checking if logged in user is directory owner
✔ Checking current folder permissions
+ sudo systemctl is-active ghost_undefined
✔ Validating config
✔ Checking folder permissions
✔ Checking file permissions
✔ Checking content folder ownership
✔ Checking memory availability
✔ Checking binary dependencies
✖ Checking systemd unit file
✖ Checking systemd node version
One or more errors occurred.

1) SystemError

Message: Unable to load or parse systemd unit file


2) SystemError

Message: Unable to determine node version in use by systemd
Help: Ensure 'ExecStart' exists in /lib/systemd/system/ghost_undefined.service and uses a valid Node version

Debug Information:
    OS: Ubuntu, v20.04.3 LTS
    Node Version: v14.17.0
    Ghost Version: 4.16.0
    Ghost-CLI Version: 1.17.4
    Environment: production
    Command: 'ghost start'

Try running ghost doctor to check your system for known issues.

You can always refer to https://ghost.org/docs/ghost-cli/ for troubleshooting.

Ever get this solved?