Apache is dead after upgrading Debian and Kolab

[Thomas Luft]

Hi there,

I just upgraded Debian 7.0 to 8.1 and also Kolab 3.3 to 3.4. Everything 
worked fine, but after the upgrade the apache is dead. The logfiles are 
empty and apache just does not react.

I deleted Kolab and Apache (Apache with --purge) and did a clean install 
of Apache 2.4 while having the Kolab repositories deactivated. After 
that Apache did work again. After enabling the repos again and 
re-installing Kolab I again can't access the web server and there are 
still no logs.

Does anyone have an idea where to start investigating?

Kind regards

Thomas