If the desktop (Gnome, MATE, etc) that you are using has a GUI network tool, you could try that instead of using nm-connection-editor. For example, the gnome tool (found in Settings / Network) has a Reset button.
Most errors that show up in the boot process can be ignored - they are often corrected later in the boot process. You can list errors by:
journalctl --boot --catalog --priority=err
If you think any of the errors are an indication of a real problem, you could post it here.