A web app running on CentOS 7 with Apache 2.4 recently changed its domain name from `olddomain.com` to `newdomain.com`.  The structure of the app at the `newdomain.com` is different than on the `olddomain.com`, so all requests from the `olddomain.com/anyurl` need to be redirected to the root url `newdomain.com`.  
**A new `.htaccess` file was created, and `httpd` was restarted, so why do requests for `olddomain.com/testbadurl` fail to redirect to `newdomain.com`?**  Instead, the user just gets a 404 error at `olddomain.com/testbadurl`.  
Here are the steps that were taken at the command line:  
    # nano /etc/httpd/conf/httpd.conf
        <Directory "/var/www/html">
            AllowOverride All
    # sudo systemctl restart httpd
    # cd /var/www/html

    # nano /var/www/html/.htaccess
        Options +FollowSymLinks
        RewriteEngine On
        RewriteBase /
        RewriteCond %{HTTP_HOST} !^healthprocesspartners\.com$ [NC]
        RewriteRule ^(.*)$ http://greenriverit.com [R=301,L]
    # systemctl restart httpd
Then the test user types `olddomain.com/testbadlink` in the web browser.  The logs at `nano /var/log/httpd/olddomain_com_requests.log` show a `404 error`, but there are NO LOGS at `nano /var/log/httpd/olddomain_com_error.log`.  
In case it was a permissions error, `root` typed `chown apache:apache /var/www/html/.htaccess`, but the same problem is persisting.  
**Is this an SELinux problem?  Or is the syntax of the `.htaccess` file incorrect?  Is there some other possible cause?**  
This is the first time that `.htaccess` has been used on this specific server, so there are no previous working conditions for `.htaccess` to which to refer on this server.
The complete text of `httpd.conf` is:  
    ServerRoot "/etc/httpd"
    Listen 80
    Include conf.modules.d/*.conf
    User apache
    Group apache
    ServerAdmin root@localhost
    <Directory />
        AllowOverride none
        Require all denied
    <Directory "/var/www/html">
        AllowOverride All
    <IfModule dir_module>
        DirectoryIndex index.html
    <Files ".ht*">
        Require all denied
    ErrorLog "logs/error_log"
    LogLevel warn
    <IfModule log_config_module>
        LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
        LogFormat "%h %l %u %t \"%r\" %>s %b" common
        <IfModule logio_module>
          LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
        CustomLog "logs/access_log" combined
    <IfModule alias_module>
        ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
    <IfModule mime_module>
        TypesConfig /etc/mime.types
        AddType application/x-compress .Z
        AddType application/x-gzip .gz .tgz
        AddType text/html .shtml
        AddOutputFilter INCLUDES .shtml
    AddDefaultCharset UTF-8
    <IfModule mime_magic_module>
        MIMEMagicFile conf/magic
    EnableSendfile on
    IncludeOptional conf.d/*.conf