Problem scenario
You try to enable a service with this command: sudo systemctl enable foobar
But you get this error: "Failed to execute operation: Invalid argument"
What should you do?
Solution
1. Find the .service file for foobar (e.g., /etc/systemd/system/foobar.service).
2. Find the "Install" section. Is there an extra character? Make sure the line looks right. If you still have a problem, you may want to see this posting's "Possible solution #2" as a guide to creating your own .service file.
Thank you. Commented out an Alias in install_section like “aaa_aa_aaa”. The underscore created the error message.