Q:

apache virtualhosts configuration problems cause 404 or test page

I have a CentOS7 server, and I have deploied WordPress based on Apache2.4.6. 
I used Certbot to deploy my certificate, it required me to open virtualhost *:80, when I finished viturehost configuration, added 127.0.0.1       example.com to hosts and got the certificate, my page shows the default Apache test page rather than my home page, and I didn't move any files which in WordPress root directory/var/www/html. 
Here's my httpd.conf file. 
<VirtualHost *:80> 
        DocumentRoot "/var/www/html/"       
        ServerName example.com                     
        ServerAlias www.example.com  
        <Directory /var/www/html/>
            Options Indexes FollowSymLinks ExecCGI
            Require all granted
            AllowOverride All
        </Directory>
        ErrorLog "logs/slg-error.log"
        CustomLog "logs/slg-access.log" common
        RewriteEngine on
        RewriteCond %{SERVER_NAME} =example.com [OR]
        RewriteCond %{SERVER_NAME} =www.example.com
        RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

Here's .htacess file in WordPress root drectory
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} ! -f
RewriteCond %{REQUEST_FILENAME} ! -d
RewriteRule .  /index.php [L]
</IfModule>

# END WordPress

Please note that I have enabled allowoverride AllowOverride All and require all Require all granted in file httpd.conf.  But here's something wrong in this part: 
#
# Deny access to the entirety of your server's filesystem.  You must
# explicitly permit access to web content directories in other 
# <Directory> blocks below. 
#
<Directory />
    AllowOverride All
    Require all denied
</Directory>

When I set Require all to denied, it will show the default page, but when I set it to Require all granted, it will show 404 NOT FOUND PAGE:The requested URL / was not found on this server.  
Here's virtualhost:443
Please note that the Carbot I used to install ertificate is automatic, so I didn't edit the file ssl.conf
<VirtualHost _default_:443>

# General setup for the virtual host, inherited from global configuration
#DocumentRoot "/var/www/html"
#ServerName www.example.com:443

# Use separate log files for the SSL virtual host; note that LogLevel
# is not inherited from httpd.conf. 
ErrorLog logs/ssl_error_log
TransferLog logs/ssl_access_log
LogLevel warn

#   SSL Engine Switch:
#   Enable/Disable SSL for this virtual host. 
SSLEngine on

#   SSL Protocol support:
# List the enable protocol levels with which clients will be able to
# connect.   Disable SSLv2 access by default:
SSLProtocol all -SSLv2 -SSLv3

#   SSL Cipher Suite:
#   List the ciphers that the client is permitted to negotiate. 
#   See the mod_ssl documentation for a complete list. 
SSLCipherSuite HIGH:3DES:!aNULL:!MD5:!SEED:!IDEA

#   Speed-optimized SSL Cipher configuration:
#   If speed is your main concern (on busy HTTPS servers e.g.),
#   you might want to force clients to specific, performance
#   optimized ciphers.  In this case, prepend those ciphers
#   to the SSLCipherSuite list, and enable SSLHonorCipherOrder. 
#   Caveat: by giving precedence to RC4-SHA and AES128-SHA
#   (as in the example below), most connections will no longer
#   have perfect forward secrecy - if the server's key is
#   compromised, captures of past or future traffic must be
#   considered compromised, too. 
#SSLCipherSuite RC4-SHA:AES128-SHA:HIGH:MEDIUM:!aNULL:!MD5
#SSLHonorCipherOrder on 

#   Server Certificate:
# Point SSLCertificateFile at a PEM encoded certificate.   If
# the certificate is encrypted, then you will be prompted for a
# pass phrase.   Note that a kill -HUP will prompt again.   A new
# certificate can be generated using the genkey(1) command. 
SSLCertificateFile /etc/pki/tls/certs/localhost.crt

#   Server Private Key:
#   If the key is not combined with the certificate, use this
#   directive to point at the key file.   Keep in mind that if
#   you've both a RSA and a DSA private key you can configure
#   both in parallel (to also allow the use of DSA ciphers, etc.) 
SSLCertificateKeyFile /etc/pki/tls/private/localhost.key

#   Server Certificate Chain:
#   Point SSLCertificateChainFile at a file containing the
#   concatenation of PEM encoded CA certificates which form the
#   certificate chain for the server certificate.  Alternatively
#   the referenced file can be the same as SSLCertificateFile
#   when the CA certificates are directly appended to the server
#   certificate for convinience. 
#SSLCertificateChainFile /etc/pki/tls/certs/server-chain.crt

#   Certificate Authority (CA):
#   Set the CA certificate verification path where to find CA
#   certificates for client authentication or alternatively one
#   huge file containing all of them (file must be PEM encoded)
#SSLCACertificateFile /etc/pki/tls/certs/ca-bundle.crt

#   Client Authentication (Type):
#   Client certificate verification type and depth.   Types are
#   none, optional, require and optional_no_ca.   Depth is a
#   number which specifies how deeply to verify the certificate
#   issuer chain before deciding the certificate is not valid. 
#SSLVerifyClient require
#SSLVerifyDepth  10

#   Access Control:
#   With SSLRequire you can do per-directory access control based
#   on arbitrary complex boolean expressions containing server
#   variable checks and other lookup directives.   The syntax is a
#   mixture between C and Perl.   See the mod_ssl documentation
#   for more details. 
#<Location />
#SSLRequire (    %{SSL_CIPHER} ! ~ m/^(EXP|NULL)/ \
#            and %{SSL_CLIENT_S_DN_O} eq "Snake Oil, Ltd." \
#            and %{SSL_CLIENT_S_DN_OU} in {"Staff", "CA", "Dev"} \
#            and %{TIME_WDAY} >= 1 and %{TIME_WDAY} <= 5 \
#            and %{TIME_HOUR} >= 8 and %{TIME_HOUR} <= 20       ) \
#           or %{REMOTE_ADDR} =~ m/^192\.76\.162\.[0-9]+$/
#</Location>

#   SSL Engine Options:
#   Set various options for the SSL engine. 
#   o FakeBasicAuth:
#     Translate the client X.509 into a Basic Authorisation.   This means that
#     the standard Auth/DBMAuth methods can be used for access control.   The
#     user name is the `one line' version of the client's X.509 certificate. 
#     Note that no password is obtained from the user.  Every entry in the user
#     file needs this password: `xxj31ZMTZzkVA'. 
#   o ExportCertData:
#     This exports two additional environment variables: SSL_CLIENT_CERT and
#     SSL_SERVER_CERT.  These contain the PEM-encoded certificates of the
#     server (always existing) and the client (only existing when client
#     authentication is used).  This can be used to import the certificates
#     into CGI scripts. 
#   o StdEnvVars:
#     This exports the standard SSL/TLS related `SSL_*' environment variables. 
#     Per default this exportation is switched off for performance reasons,
#     because the extraction step is an expensive operation and is usually
#     useless for serving static content.  So one usually enables the
#     exportation for CGI and SSI requests only. 
#   o StrictRequire:
#     This denies access when "SSLRequireSSL" or "SSLRequire" applied even
#     under a "Satisfy any" situation, i.e. when it applies access is denied
#     and no other module can change it. 
#   o OptRenegotiate:
#     This enables optimized SSL connection renegotiation handling when SSL
#     directives are used in per-directory context.  
#SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire
<Files ~ "\.(cgi|shtml|phtml|php3?)$">
    SSLOptions +StdEnvVars
</Files>
<Directory "/var/www/cgi-bin">
    SSLOptions +StdEnvVars
</Directory>

#   SSL Protocol Adjustments:
#   The safe and default but still SSL/TLS standard compliant shutdown
#   approach is that mod_ssl sends the close notify alert but doesn't wait for
#   the close notify alert from client.  When you need a different shutdown
#   approach you can use one of the following variables:
#   o ssl-unclean-shutdown:
#     This forces an unclean shutdown when the connection is closed, i.e. no
#     SSL close notify alert is send or allowed to received.   This violates
#     the SSL/TLS standard but is needed for some brain-dead browsers.  Use
#     this when you receive I/O errors because of the standard approach where
#     mod_ssl sends the close notify alert. 
#   o ssl-accurate-shutdown:
#     This forces an accurate shutdown when the connection is closed, i.e. a
#     SSL close notify alert is send and mod_ssl waits for the close notify
#     alert of the client.  This is 100% SSL/TLS standard compliant, but in
#     practice often causes hanging connections with brain-dead browsers.  Use
#     this only for browsers where you know that their SSL implementation
#     works correctly.  
#   Notice: Most problems of broken clients are also related to the HTTP
#   keep-alive facility, so you usually additionally want to disable
#   keep-alive for those clients, too.  Use variable "nokeepalive" for this. 
#   Similarly, one has to force some clients to use HTTP/1.0 to workaround
#   their broken HTTP/1.1 implementation.  Use variables "downgrade-1.0" and
#   "force-response-1.0" for this. 
BrowserMatch "MSIE [2-5]" \
         nokeepalive ssl-unclean-shutdown \
         downgrade-1.0 force-response-1.0

#   Per-Server Logging:
#   The home of a custom SSL log file.  Use this when you want a
#   compact non-error SSL logfile on a virtual host basis. 
CustomLog logs/ssl_request_log \
          "%t %h %{SSL_PROTOCOL}x %{SSL_CIPHER}x \"%r\" %b"

</VirtualHost>    

Problems resolved. 
Here's the Virtualhost:443 I configured. 

#Listen 443 https

<VirtualHost *:443>

# General setup for the virtual host, inherited from global configuration
DocumentRoot "/var/www/html"
ServerName example.com
    <Directory "/var/www/html">
    allow from all
    AllowOverride all
    Options Indexes FollowSymLinks ExecCGI
    </Directory>
...

</VirtualHost>     

Any help and suggestions will be very appreciated. 

A:

Please start from removing the dot from documentRoot and Directory:

        DocumentRoot "./var/www/html/"

to 

        DocumentRoot "/var/www/html/"

then post the results.  All other things look pretty good IMO. 
NOT starting with a slash makes the path relative and I think that's the issue you have right now.