Issue Reverse Proxy Server (nginx) won't enable

[Fabix]

I have installed Reverse Proxy Server (nginx). When I try to start it I receive the error:
Unable to start service: Unable to manage service by nginxmng: ('start', 'nginx'). Error: [2018-12-12 17:27:26.334] ERR [util_exec] proc_close() failed ['/usr/local/psa/admin/bin/nginx_control' '--start'] with exit code [1] Can not start proxy server

When this error is showed, the website is not more reachable. To restore the service I must enter via ssh and execute the command:
/usr/local/psa/admin/sbin/nginxmng -d

I have already tryed all the fix in your support pages, but without success.

Thank you,
F.

 

[IgorG]

What is the output of command

# nginx -t

And have you tried to repair webserver settings with

# plesk repair web

?