letsencrypt.sh fails but letsencrypt-standalone.sh succeeds

[meta-meta]

I'm wondering what might cause letsencrypt.sh to fail. Could it be that certbot was unable to create a file in .wellknown/acme-challenge/? When I was working through the initial setup, sudo cp -R ninjam-web /var/www/ninjam-web failed because I did not have a /var/www/. This is on a fresh Amazon Linux AMI. I'm not sure what the expectation is as I'm not very experienced with devops and linux in general. Learning.

From inside the container:

root@12345:/# /etc/ninjam/letsencrypt.sh
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator webroot, Installer None
Starting new HTTPS connection (1): acme-v02.api.letsencrypt.org
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for mydomain.com
http-01 challenge for www.mydomain.com
Using the webroot path /app/src/public for all unmatched domains.
Waiting for verification...
Cleaning up challenges
Failed authorization procedure. mydomain.com (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching http://mydomain.com/.well-known/acme-challenge/zUX21CIZFhMEp3E3HrUXz10cZuS7cLkh7AATrWZHqzw: Connection refused, www.mydomain.com (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching http://www.mydomain.com/.well-known/acme-challenge/_PEjA7U2KvIG0Gbpdu9LfnpYhluk7VXcffNlp39H7CA: Connection refused

IMPORTANT NOTES:
 - The following errors were reported by the server:

   Domain: mydomain.com
   Type:   connection
   Detail: Fetching
   http://mydomain.com/.well-known/acme-challenge/zUX21CIZFhMEp3E3HrUXz10cZuS7cLkh7AATrWZHqzw:
   Connection refused

   Domain: www.mydomain.com
   Type:   connection
   Detail: Fetching
   http://www.mydomain.com/.well-known/acme-challenge/_PEjA7U2KvIG0Gbpdu9LfnpYhluk7VXcffNlp39H7CA:
   Connection refused

   To fix these errors, please make sure that your domain name was
   entered correctly and the DNS A/AAAA record(s) for that domain
   contain(s) the right IP address. Additionally, please check that
   your computer has a publicly routable IP address and that no
   firewalls are preventing the server from communicating with the
   client. If you're using the webroot plugin, you should also verify
   that you are serving files from the webroot path you provided.
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
cp: cannot stat '/etc/letsencrypt/live/mydomain.com/privkey.pem': No such file or directory
cp: cannot stat '/etc/letsencrypt/live/mydomain.com/fullchain.pem': No such file or directory
 * Reloading nginx configuration nginx     

root@12345:/# etc/ninjam/letsencrypt-standalone.sh
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator standalone, Installer None
Starting new HTTPS connection (1): acme-v02.api.letsencrypt.org
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for mydomain.com
http-01 challenge for www.mydomain.com
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/mydomain.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/mydomain.com/privkey.pem
   Your cert will expire on 2020-10-11. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot
   again. To non-interactively renew *all* of your certificates, run
   "certbot renew"
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

 * Reloading nginx configuration nginx                                     

[ayvan]

I have no idea what causes this problem. Just ran the script and successfully renewed the certificate.
Please, check your nginx configs (/etc/nginx/nginx.conf and /etc/ngins/sites-available/default.conf) in your container.