Missing some Visitors

Hi all,
we have some visitors which are found in apache logging, but they are missing in our Piwik Database.
The difference is up to 50% for some Sites. There are no affecting Filters for these hits.
Any suggestions? Please advise.

Try to disable “Do Not Track” support in Settings-> Privacy. IE has “DnT” enabled by default so it may be the cause. You may also visit Statistics from Piwik and my other web analytics tool (log analyzer, webalizer or javascript based) are different, why? - Analytics Platform - Matomo