Error reading preface from client

Trying to setup my simple site

caddyfile: {
  ext .html .md

  tls my-adress@used-for-certs.demo  # automatic tls, create or renew certs
  root /var/www       # static files

ports are open ufw status:

80/tcp                     ALLOW IN    Anywhere                  
443/tcp                    ALLOW IN    Anywhere                  
80/tcp (v6)                ALLOW IN    Anywhere (v6)             
443/tcp (v6)               ALLOW IN    Anywhere (v6)             

page loads, seems working (browsing with safari, chrome or firefox ) but
log shows error-message:

Jun 23 10:10:11 caddy[5668]: 2016/06/23 10:10:11 http2: server: error reading preface from client [2003:c3:abc6:700:57a:e7c8:13f0:3f6b]:55993: timeout waiting for client preface

I’m not able to figure out, what I’m doing wrong
thx in advance

Hello Achim, welcome to the Caddy forum! :slight_smile:

I searched around for this error, and found the relevant error in the http2 package:

It looks like the client might not be sending a proper request. But I’m not really sure exactly.
@matt what do you think?

@jacob yeah, thx. I also tried to google first and found these. But I don’t know what it should tell me and where to start with.

Well since it’s an issue in the http2 package this may be a better issue to raise with them.

Yeah I see these too sometimes but with no known ill effects. It could be a bug in the http2 implementation or it is probably something wacky that browsers are doing. They do strange things with connections; debugging server-side with browsers is generally a bad idea because of their complexity. Instead, try a simpler HTTP client like curl.

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