Issue Problem to create more than 500 Subscriptions

[Mann87]

Hi, we use the Plesk API to create subscriptions for our customers. We use two servers with about 500 subscriptions now without any problems. They both reached now 500. But now we got failures by trying to create more. The problem is on both servers.

Our Servers:
Intel Xeon E5 1650v2
64 GB RAM
SSD-Drives
CentOS 7

Plesk:
Plesk Onyx v17.0.17_build1700161028.14 os_CentOS 7
Installations without Nginx, only minimal selections

Error message:
error 2204 Unable to update hosting preferences. phpinimng failed: Job for php-fpm.service failed because the control process exited with error code. See "systemctl status php-fpm.service" and "journalctl -xe" for details. Failed to reload php-fpm service

Someone an idea how to solve that?

 

[Bitpalast]

What is the output of
# systemctl status php-fpm.service
# journalctl -xe
?