Error 503 with presence builder

[GuilhermeX]

Hi,

Every time a customer create a website with presence builder, after publish, he gets "Error 503, service is unavaliable" for it's site. We try to develop the website with another software, most like presence builder (PB), and upload the files to plesk. It works like haven. if we go back to PB, it gets the error.
Server: Virtualbox - windows 2008 STD - 3.5GB of memory, 50Gb of HDD (data only and 80% free), 50Gb of HDD for windows (40% free), 3 cores 3.5GHZ;
Host: windows 7 ultimate, 16GB of memory, 2x 500GB HDD raid 1 (data only - 80% free), 8core, 3.5GHZ.
Any help will be appreciated.

 

[IgorG]

In case of Virtuozzo it may occur due to lack of resources, for example. http://kb.parallels.com/en/119200

 

[GuilhermeX]

In case of Virtuozzo it may occur due to lack of resources, for example. http://kb.parallels.com/en/119200

I'm not using Virtuozzo. I'm using Oracle Virtualbox. The host and guest have a lot of resource available.