Received the following error message when attempting to restart a network service recently. I do not have a technical explanation for what this means, however, i believe it may be attributed to using a proxy port forwarded – or possibly upgrading the image on disk while the service was running:
Unit -.mount is masked.
The accepted solution has been suggested as:
sudo systemctl unmask servicename
Unfortunately in my situation, this command did not return the ability to stop / restart the service in question – rebooting seems to of solved the issue.