Plesk 12.x / Linux :: Vhosts On One Of Two IP Addresses

I have a Problem with my VHosts on one of two IP addresses. One IP is dedicated and works well

The other IP is shared. Since two days every call to one of the websites of this share ip goes to the Plesk Default Website. I tried to reconfigure single sites and all sites (/usr/local/psa/admin/bin/httpdmng --reconfigure-all), nothing works and restarting apache shows some warnings.

apache2ctl -S shows the following lines:

Code:

[Mon Dec 01 19:56:08 2014] [warn] VirtualHost 85.214.41.141:7080 overlaps with VirtualHost 85.214.41.141:7080, the first has precedence, perhaps you need a NameVirtualHost directive
[Mon Dec 01 19:56:08 2014] [warn] VirtualHost 85.214.41.141:7081 overlaps with VirtualHost 85.214.41.141:7081, the first has precedence, perhaps you need a NameVirtualHost directive

[Code] ....

In an other thread I found a possible solution for the overlapping vhosts. The problem there seems to be a missing ssl-certificate and that matches with the situation on my server. After copying any other certificate-file as the one with the missing filename the apache starts without any warnings, but after that all websites (the sites from the dedicated ip too) only shows the apache default site ("it works"). I Tried to reconfigure single sites and all sites (/usr/local/psa/admin/bin/httpdmng --reconfigure-all), nothing works.

The server is hosted by STRATO, so there are daily backups. I turned back one week (the problem exists since two days). Then for some hours all works fine but suddenly all the sites on the ip 85.214.41.141 get broken again and shows only plesks default page.