Disable the need to resolve the hostname by
<code>
echo 'yes' > /etc/pure-ftpd/conf/DontResolve
</code>

Also get a verbose log by
<code>
echo 'yes' > /etc/pure-ftpd/conf/VerboseLog
</code>

You can remove the verbose logging with a simple
<code>
rm -f /etc/pure-ftpd/conf/VerboseLog
</code>