A slightly edited version of the Virtual Host definition in RiggsFolly's answer on stackoverflow worked for crm2plus.ddns.net
<VirtualHost *:80>
ServerName crm2plus.ddns.net
ServerAlias crm2plus.ddns.net
ServerRoot /var/www/crm2plus.ddns.net/
DocumentRoot /var/www/crm2plus.ddns.net/public_html
<Directory "/var/www/crm2plus.ddns.net/public_html">
Options +Indexes +FollowSymLinks
Order allow,deny
Allow from all
AllowOverride All
</Directory>
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
ErrorLog ${APACHE_LOG_DIR}/crm2plus.ddns.net_error.log
CustomLog ${APACHE_LOG_DIR}/crm2plus.ddns.net_access.log combined
</VirtualHost>