# Install rainloop

  1) # wget https://www.rainloop.net/repository/webmail/rainloop-community-latest.zip
    or
    # https://www.rainloop.net/repository/webmail/rainloop-latest.zip   
  2) # unzip rainloop-community-latest.zip  -d /usr/share/rainloop
  3) # find /usr/share/rainloop -type d -exec chmod 755 {} \;
  4) # find /usr/share/rainloop -type f -exec chmod 644 {} \;
  5) # chown -R apache:apache /usr/share/rainloop
 6a) # vi /etc/httpd/conf.d/rainloop.conf (CentOS 7/8)
 #
 # Rainloop Webmail is a browser-based multilingual IMAP client
 #

 RewriteEngine On
 RewriteCond %{HTTPS} off
 RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

 Alias /rlmail /usr/share/rainloop

 <Directory /usr/share/rainloop/>
     Options +Indexes +FollowSymLinks +ExecCGI
     AllowOverride All
     Require all granted
     #ErrorLog "/var/log/httpd/rainloop_error_log"
     #TransferLog "/var/log/httpd/rainloop_access_log"
 </Directory>

 <Directory /usr/share/rainloop/data/>
     Require all denied
 </Directory>

 6b) vi /etc/httpd/conf.d/rainloop.conf (CentOS 6)
 #
 # Rainloop Webmail is a browser-based multilingual IMAP client
 #

 RewriteEngine On
 RewriteCond %{HTTPS} off
 RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

 Alias /rlmail /usr/share/rainloop

 <Directory /usr/share/rainloop/>
   Options -Indexes
   AllowOverride All
 </Directory>

 <Directory /usr/share/rainloop/data>
   Order Deny,Allow
   Deny from All
 </Directory>

  7) # yum -y install php-xml
  8) # systemctl restart httpd

 # Configure, help
  8) https://yourserver/rlmail/?admin/
    username: admin
    password: 12345
  9) Change admin password
 10) Add your domain, IMAP server, SMTP server, ...Do not use short login
 11) Add contact support if needed. Requires DB support.

 # Login to email account
 12) https://yourserver/rlmail 
 13) Additional Tutorial
 14) 2-Factor Authentication