New version 12.5.30: website gives 500 internal server error

Hello there!

After the (automatic) upgrade to Plesk v12.5.30_build1205150826.19 (os_CentOS 6) my websites generate 500 internal server error.

The logs show: (104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server

I tried: https://kb.plesk.com/en/120785 and still no luck.

Any ideas?