golang autocert acme/autocert: missing server name - go

Question

i use Library autocert in my application for generate ssl certificate, problem is 30% of users have problem with my application, my current code is :
fmt.Println("Starting server on " + this.Params.Bind)
if this.Params.SSL {
fmt.Println("SSL Enabled")
m := autocert.Manager{
Prompt: autocert.AcceptTOS,
HostPolicy: autocert.HostWhitelist(this.Params.HostsWhitelist...),
Cache: autocert.DirCache(this.Params.CertCache),
}
log.Fatal(autotls.RunWithManager(r, &m))
} else {
r.Run(this.Params.Bind)
}
the errors is :
2018/12/03 12:37:33 http: TLS handshake error from 68.71.48.249:55885: acme/autocert: missing server name
2018/12/03 12:37:33 http: TLS handshake error from 209.213.121.223:38284: acme/autocert: missing server name
2018/12/03 12:37:33 http: TLS handshake error from 209.213.121.223:38283: acme/autocert: missing server name
2018/12/03 12:37:33 http: TLS handshake error from 68.71.48.249:55887: acme/autocert: missing server name
2018/12/03 12:37:33 http: TLS handshake error from 68.71.48.249:55888: acme/autocert: missing server name
2018/12/03 12:37:33 http: TLS handshake error from 209.237.150.145:56842: acme/autocert: missing server name
how i can fix error missing server name ?

Answer 1

Maybe my blog will help you find a difference in your code vs the code I show in my blog.
https://marcofranssen.nl/build-a-go-webserver-on-http-2-using-letsencrypt/
Furthermore I figured out there is a much better library available to manage certificates via Letsencrypt.
https://marcofranssen.nl/use-the-acme-dns-challenge-to-get-a-tls-certificate/
In this second blog I utilize https://go-acme.github.io/lego/ which is supporting more of the ACME challenges. It ships with a cli, but can also be used as a lib in your webserver. In fact it is used in Traefik as well the Caddy webserver project.
You also should NOT use the SNI challenge anymore as it is considered insecure. Instead use the ALPN challenge.