Solution to Unison user 'root' is not allowed to use incron Error

If you receive the following error while synchronizing folders between servers using Unison, the reason for the error is that the root user cannot be used because dangerous operations can be performed for Incron.

For the solution:

echo 'root' >> /etc/incron.allow

or

You can exit by opening the /etc/incron.allow file with nano, typing root, saving the file and exiting. The changes made are valid immediately.