Resolved nginx error

[nethu mshan]

when i'm seeing log files i'm seeing this 3 error messages. how can i fix this?

26702#0: *3738686 connect() failed (111: Connection refused) while connecting to upstream

26702#0: *3739037 peer closed connection in SSL handshake (104: Connection reset by peer) while SSL handshaking to upstream

[proxy_fcgi:error] [pid 6639:tid 139858395739904] (70007)The timeout specified has expired: [client xxx.xx.xx.xxx:35812] AH01075: Error dispatching request to : (polling), referer: https://example.com

 

[Brujo]

Maybe you like to start with some knowledgebase article like
[HUB] 502 Bad Gateway
Websites on Plesk do not work on HTTPs: 502 Bad Gateway: connect() failed (111: Connection refused)

AH01075: Error dispatching request to
Website is down: Service Temporarily Unavailable: AH01075: Error dispatching request to
WordPress website shows 503 Service Temporarily Unavailable: AH01075: Error dispatching request to