Plesk 12.x / Linux :: Nginx - 502 Bad Gateway With Every Domain Change

Since we switched to Plesk 12 and activated nginx the problem reoccurs reliably on every domain change.
As soon as a customer creates a new domain or alias and Apache restarts nginx delivers 502 errors for maybe 10 seconds. After that everything is fine again.

The system is Debian 6.0.10 with Plesk 12.0.18 Update #38

That might not be a problem in small environments, but with >100 domains the timeout is annoying enough for customers to pick up the phone.

Adding this to /etc/sw-cp-server/config did not do the trick.

http {
fastcgi_buffers 32 32k;
fastcgi_buffer_size 64k;
fastcgi_read_timeout 600;
fastcgi_send_timeout 600;
}