Renewal of letsencrypt does not restart/reload nginx

short description

When renew letsencrypt certificates from domains in nginx service the nginx service will not restart in debian9. So it may happen, that a non valid certificate is send by nginx to clients instead of the newly generated one.

correct behaviour

After renew of letsencrypt nginx should be restarted. On a debian stretch with apache as webserver it works.

environment

Server OS: Debian
Server OS version: Stretch
ISPConfig version: 3.1.11

nginx version: nginx/1.10.3

Not sure, but I think the problem is in 900-letsencrypt.inc.php in line 71 - systemctl force-reload nginx does not work.

I had not tracked down what is realy send at this point but wouldn't be a restart better for nginx?

Bye

Rajko