Running Certbot after setting up Streisand - failed

[Vista2003]

Expected behaviour: Running Certbot after installation since I can't use Certbot during Streisand's installation.

Certbot to issue a new SSL cert for the server

Actual Behavior:

Domain: DOMAIN
Type: connection
Detail: Fetching
http://DOMAIN/.well-known/acme-challenge/REDACTED
Timeout during connect (likely firewall problem)

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.

Steps to Reproduce:

1. install Streisand without Let's Encypt
2. Running Certbot after the fact

Additional Details:

*Operating System of target host: Ubuntu 16.04

*Operating System of client: N/A