Websites are unavailable in Plesk: 502 Bad Gateway - SSL: error:1408F10B:SSL routines:ssl3_get_record:wrong version number

Symptoms

• All domains are unaccessible with the error:

  CONFIG_TEXT: 502 Bad Gateway

• The following error can be found at domain's nginx error log /var/www/vhosts/<domain_name>/logs/proxy_error_log:

  CONFIG_TEXT: [error] 3755#0: *2278 SSL_do_handshake() failed (SSL: error:1408F10B:SSL routines:ssl3_get_record:wrong version number) while SSL handshaking to upstream, client: 203.0.113.4, server: www.example.com, request: "GET / HTTP/2.0", upstream: "https://203.0.113.2:7081/", host: "www.example.com"

• Nginx, Apache, MySQL services are up and running.

• Plesk nginxmng utility shows that nginx is Disabled:

  # plesk sbin nginxmng -s
  Disabled

Cause

Unclear

Resolution

1. Connect to the server via SSH

2. Enable Nginx by running the following Plesk command:

   # plesk sbin nginxmng -e