Does anyone know how to fix it?
https://idfr.com/checkout/onepage/


Not Found
The requested URL /checkout/onepage/ was not found on this server.
Apache/2.4.7 (Ubuntu) Server at idfr.com Port 443



Here's part of the content of my 000-default.conf in sites-enabled:
<VirtualHost 66.228.42.136:80>
ServerAdmin info@idfr.com
DocumentRoot /var/www/idfr

<Directory /var/www/idfr/>
Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
Allow from all
</Directory>

ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined

</VirtualHost>

Listen 443
<VirtualHost *:443>

DocumentRoot /var/www/idfr
ServerName http://www.idfr.com

SSLEngine on
SSLCertificateFile "/etc/apache2/ssl/www_idfr_com.crt"
SSLCertificateKeyFile "/etc/apache2/ssl/www.idfr.com.key"
SSLCACertificateFile "/etc/apache2/ssl/www_idfr_com.ca-bundle"

</VirtualHost>

What are the contents of the /var/www/idfr/checkout/onepage/ directory on your server?

The 404 or Not Found error message is an HTTP standard response code indicating that the client was able to communicate with a given server, but the server could not find what was requested.

I found there's no such folder named checkout in the directory /var/www/idfr. Before I added the SSL, the checkout works fine though.

How can I solve this issue?

Retrace your steps to see what went wrong.

Your URL has a checkout folder but you see there isn't one. Either you're missing files or an .htaccess file isn't handling redirects correctly.

Also, you can run something like `apache2ctl -S` to see if your vhost and loaded properly.

Below is the return for `apache2ctl -S`, does it look normal?

VirtualHost configuration:
66.228.42.136:80 is a NameVirtualHost
default server idfr.com (/etc/apache2/sites-enabled/000-default.conf:32)
port 80 namevhost idfr.com (/etc/apache2/sites-enabled/000-default.conf:32)
port 80 namevhost idfr.com (/etc/apache2/sites-enabled/idfr.com-backup.conf:11)
alias http://www.idfr.com
23.239.9.57:80 broadfeet.com (/etc/apache2/sites-enabled/000-default.conf:1)
*:443 http://www.idfr.com (/etc/apache2/sites-enabled/000-default.conf:89)
*:80 is a NameVirtualHost
default server broadfeet.com (/etc/apache2/sites-enabled/broadfeet.com-backup.conf:1)
port 80 namevhost broadfeet.com (/etc/apache2/sites-enabled/broadfeet.com-backup.conf:1)
alias http://www.broadfeet.com
port 80 namevhost broadfeet.com (/etc/apache2/sites-enabled/broadfeet.com-backup.conf:32)
alias broadfeet.com
port 80 namevhost broadfeet.com (/etc/apache2/sites-enabled/broadfeet.com.conf:1)
alias http://www.broadfeet.com
port 80 namevhost broadfeet.com (/etc/apache2/sites-enabled/broadfeet.com.conf:32)
alias broadfeet.com
port 80 namevhost idfr.com (/etc/apache2/sites-enabled/idfr.com.conf:11)
alias http://www.idfr.com
port 80 namevhost idfr.com (/etc/apache2/sites-enabled/idfr.com.conf:55)
alias idfr.com
port 80 namevhost broadfeet.com (/etc/apache2/sites-available/broadfeet.com.conf:1)
alias http://www.broadfeet.com
port 80 namevhost broadfeet.com (/etc/apache2/sites-available/broadfeet.com.conf:32)
alias broadfeet.com
port 80 namevhost idfr.com (/etc/apache2/sites-available/idfr.com.conf:11)
alias http://www.idfr.com
port 80 namevhost idfr.com (/etc/apache2/sites-available/idfr.com.conf:55)
alias idfr.com
ServerRoot: "/etc/apache2"
Main DocumentRoot: "/var/www"
Main ErrorLog: "/var/log/apache2/error.log"
Mutex ssl-stapling: using_defaults
Mutex ssl-cache: using_defaults
Mutex default: dir="/var/lock/apache2" mechanism=fcntl
Mutex mpm-accept: using_defaults
Mutex authdigest-opaque: using_defaults
Mutex watchdog-callback: using_defaults
Mutex rewrite-map: using_defaults
Mutex authdigest-client: using_defaults
PidFile: "/var/run/apache2/apache2.pid"
Define: DUMP_VHOSTS
Define: DUMP_RUN_CFG
User: name="www-data" id=33
Group: name="www-data" id=33

Also, here is the rewrite code in .htaccess:
############################################
## enable rewrites

Options +FollowSymLinks
RewriteEngine on
RewriteCond %{REQUEST_URI} checkout\/onepage
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L]

############################################