Using rsync in crontab of different user than root requires adding additional ENV variables. Example:

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh

53 14 * * * rsync -aq root@example.com:/root/backups/ /home/user/Documents/backups/
30 14 * * 1 rsync -aq root@example.org:/root/backup/* /home/user/Documents/backup/

• http://serverfault.com/questions/92683/execute-rsync-command-over-ssh-with-an-ssh-agent-via-crontab