There are a few potential reasons for this error. It could be that the Monero daemon files are not in the correct directory, or it could be that you don’t have the correct permissions set on the files. If you’re not sure what permission settings to use, you can try running the Monero daemon with the -allow-rpc-admin-commands flag. This will allow you to run commands as root, which may fix the problem.
If the above doesn’t work, it’s possible that your Monero daemon is configured incorrectly. Try checking the configuration file (monerod.conf) and make sure that all of the options are set correctly. If everything looks good there, you can try starting monerod with the -reindex flag. This will rebuild the blockchain index, which may fix the problem.
If you’re still having trouble, it’s possible that your Monero daemon is corrupt or damaged. In this case, you’ll need to download a new copy of the Monero daemon and start from scratch.
Hopefully, one of the above solutions will solve your problem. If not, feel free to ask for help in the Monero forums or on IRC.
Causes of Monero daemon failed to start
If you are using UFW (Ubuntu Firewall), you need to allow port 18081 in order for the Monero daemon to work properly. To do this, open a terminal and type:
sudo ufw allow 18081/tcp
Another possible problem is that your system clock is not set correctly. The Monero daemon requires a correct system clock in order to function properly. You can check your system clock by running the date command in a terminal. If the output is incorrect, you can try setting the system clock manually with the following command:
sudo date -s “YYYY-MM-DD HH:MM:SS”
Replace “YYYY-MM-DD HH:MM:SS” with the current date and time.