I installed aaPanel on a clean setup of Ubuntu version 20. When I try to obtain an SSL certificate for my website, I encounter an access error for the directory '.well-known/acme-challenge/TcqWz7wqDRwxIWaLTeScixl9-_mDi8wL0hYT8nmbNZc'. Upon checking, I can see that the relevant folders and files exist. All the domains I have added are experiencing the same issue. Could you assist me in resolving this problem?