Haproxy Timeout Error with nginx

Hi!

I get this Error in nginx log and a Bad Gateway 502


2022/03/20 15:00:53 [error] 1124599#1124599: *22208 upstream prematurely closed connection while reading response header from upstream, client: 192.168.1.1, server: sync.xxx.ch, request: "GET / HTTP/1.1", upstream: "uwsgi://unix:/run/uwsgi/mozilla-firefox-sync-server.sock:", host: "sync.xxx.ch"

Anybody knows how to adjust my configuration for don’t get a closed connection?


#
# Automatically generated configuration.
# Do not edit this file manually.
#

global
    uid                         80
    gid                         80
    chroot                      /var/haproxy
    daemon
    stats                       socket /var/run/haproxy.socket group proxy mode 775 level admin
    nbproc                      1
    nbthread                    4
    hard-stop-after             60s
    no strict-limits
    maxconn                     10000
    tune.ssl.default-dh-param   4096
    spread-checks               2
    tune.bufsize                16384
    tune.lua.maxmem             0
    log                         /var/run/log local0 info
    lua-prepend-path            /tmp/haproxy/lua/?.lua

defaults
    log     global
    option redispatch -1
    maxconn 5000
    timeout client 1000s
    timeout connect 1000s
    timeout server 1000s
    retries 3
    default-server init-addr libc,last
    default-server maxconn 5000

# autogenerated entries for ACLs


# autogenerated entries for config in backends/frontends

# autogenerated entries for stats




# Frontend: SNI_frontend (Listening o)
frontend SNI_frontend
    bind 0.0.0.0:443 name 0.0.0.0:443 
    bind 0.0.0.0:80 name 0.0.0.0:80 
    bind :::80 name :::80 
    bind :::443 name :::443 
    mode tcp
    default_backend SSL_backend
    # tuning options
    timeout client 1000s

    # logging options

# Frontend: HTTP_frontend (Listening 127.0.0.1:80)
frontend HTTP_frontend
    bind 127.0.0.1:80 name 127.0.0.1:80 accept-proxy 
    bind [::1]:80 name [::1]:80 accept-proxy 
    mode http
    option http-keep-alive
    option forwardfor
    # tuning options
    timeout client 1000s

    # logging options
    # ACL: NoSSL_condition
    acl acl_621d0b77c74989.24704837 ssl_fc

    # ACTION: HTTPtoHTTPS_rule
    http-request redirect scheme https code 301 if !acl_621d0b77c74989.24704837

# Frontend: HTTPS_frontend (Listinging on 127.0.0.1:443)
frontend HTTPS_frontend
    http-response set-header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload"
    bind 127.0.0.1:443 name 127.0.0.1:443 accept-proxy ssl curves secp384r1  no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets ciphers ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES256-GCM-SHA384 ciphersuites TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256 alpn h2,http/1.1 crt-list /tmp/haproxy/ssl/621d11c7cad951.61400293.certlist 
    bind [::1]:443 name [::1]:443 accept-proxy ssl curves secp384r1  no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets ciphers ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES256-GCM-SHA384 ciphersuites TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256 alpn h2,http/1.1 crt-list /tmp/haproxy/ssl/621d11c7cad951.61400293.certlist 
    mode http
    option http-keep-alive
    default_backend WEBSERVER_backend
    option forwardfor
    # tuning options
    timeout client 15m

    # logging options

    # ACTION: PUBLIC_SUBDOMAINS_map-rule
    # NOTE: actions with no ACLs/conditions will always match
    use_backend %[req.hdr(host),lower,map_dom(/tmp/haproxy/mapfiles/621d0c7054ddb7.46420139.txt)] 

# Backend: SSL_backend ()
backend SSL_backend
    # health checking is DISABLED
    mode tcp
    balance source
    # stickiness
    stick-table type ip size 50k expire 30m  
    stick on src
    # tuning options
    timeout connect 1000s
    timeout server 1000s
    server SSL_server 127.0.0.1 send-proxy-v2 check-send-proxy

# Backend: WEBSERVER_backend ()
backend WEBSERVER_backend
    # health checking is DISABLED
    mode http
    balance source
    # stickiness
    stick-table type ip size 50k expire 30m  
    stick on src
    # tuning options
    timeout connect 1000s
    timeout server 1000s
    # WARNING: pass through options below this line
    http-request set-header X-Forwarded-Proto https if { ssl_fc }
    http-reuse safe
    server WEBSERVER_server 192.168.1.100:80 send-proxy-v2 check-send-proxy

# Backend: NAS_backend ()
backend NAS_backend
    # health checking is DISABLED
    mode http
    balance source
    # stickiness
    stick-table type ip size 50k expire 30m  
    stick on src
    # tuning options
    timeout connect 1000s
    timeout server 1000s
    # WARNING: pass through options below this line
    http-request set-header X-Forwarded-Proto https if { ssl_fc }
    http-reuse safe
    server NAS_server 192.168.1.118:80 

# Backend: WEBSERVER_SSL_backend ()
backend WEBSERVER_SSL_backend
    # health checking is DISABLED
    mode http
    balance source
    # stickiness
    stick-table type ip size 50k expire 30m  
    stick on src
    # tuning options
    timeout connect 1000s
    timeout server 1000s
    # WARNING: pass through options below this line
    http-request set-header X-Forwarded-Proto https if { ssl_fc }
    http-reuse safe
    server WEBSERVER_server_ssl 192.168.1.100:443