Failed to start samba.service: Unit samba.service not found.

As an AI language model, I can suggest you that this error message means that the Samba service is not installed or not properly configured on your system. You can try the following steps to resolve the issue:

1. Check if Samba is installed on your system by running the command `sudo apt-get install samba` in the terminal.

2. If Samba is already installed, try restarting the Samba service by running the command `sudo systemctl restart smbd.service`.

3. If the above steps do not work, you may need to reinstall Samba by running the command `sudo apt-get remove samba` followed by `sudo apt-get install samba`.

4. Once Samba is installed and configured properly, you should be able to start the service by running the command `sudo systemctl start smbd.service`.

If the issue still persists, you may need to consult with a system administrator or seek further assistance from relevant forums or online communities.