ERR_EMPTY_RESPONSE

Hey,

this error occours pretty often (too often) and goes away after 24 hours – I have set W3 Total Cache to empty cache every 24 hours, so I guess this has something to do with W3 Total Cache:

http://www.pic-upload.de/view-23184914/error.jpg.html

Frontend of my website (cached) still works. Every uncached site and admin area does not work at all… for 24 hours when this error appears.

What´s wrong?

https://wordpress.org/plugins/w3-total-cache/