https://www.linuxbabe.com/ubuntu/install-resilio-sync-ubuntu-16-04-16-10

1. You might encounter the following error message. That’s because Resilio Sync is running as rslsync user.

Don’t have permissions to write to selected folder.

Let’s say you selected your home folder ‘/home/your-username/' as the shared folder. To fix the above error, all you need to do is to grant permissions on your home folder to the rslsync user with the following command.

$ sudo setfacl -R -m "u:rslsync:rwx" /home/your-username

The above command won’t change the owner of the shared folder. The owner has the same permissions as usual. What it does is to grant read, write and execute permissions to one more user, namely rslsync.

Now you should be able to add your home folder as the shared folder.