Resolved All websites not working after restarting server

[Jimlee3]

I am running plesk 12.0.18 on Centos 6.8 and using the control panel I restarted the server. Now none of the websites works, I can access the control panel but I get an error when viewing the websites.
I did header check and I get this message:
Error 111: Connection refused

can someone please help to fix this?

 

[Jimlee3]

I had to restart Reverse Proxy Server (nginx) from services tab and it resolved the issue