RT spawn-fcgi forks die

Hello, we are using RT-4.4.3 on an up-to-date Centos-7.

We are starting rt with the following:

spawn-fcgi -u nginx -g nginx -s /run/rt.socket -S -M 0600 -F 10 -P /run/rt.pid – rt-server.fcgi

Rt starts successfully but after some minutes I noticed that the forks die unless there will be no more forks and systemd restarts the service.

I don’t see anything in the log, is there a way to debug the issue?