Hi,
i’m trying to configure my apache to use let’s encrypt certificate (no certificate before).
i have this error message :
failed authorization procedure. [my domain] (tls-sni-01): urn:acme:error:unauthorized :: The Client lacks sufficient authorization :: Correct zName not found for TLS SNI Challenge. Found
i’m running it on an ubuntu server, using sudo…
please help, you’re my only hope ! 
same error here, but on debian and apache.
@adeniau, are you also using an internal domain or a public domain?
suggests that the domain name cannot be found on that server ( using Server Name Indication). If it's an internal domain that can't be reached externally, that would explain it (and you would need to use the "manual" method of setup). It could also be a shared hosting server, which isn't supporting SNI
it’s a public domain (ddns.net) which target a server at home. external access is ok, actually it works with no https.
Are you using a ddns.net domain name ? in shich case have a look at Blacklisted domain and DynDns/No-IP ("Managed DNS") support
using ddns.net shouldn’t generate the “zname not found” error you are seeing, however will give other issues.
Are you happy to provide your domain name to look at ?
hi, thanks for your replies. i may have an issue in my apache since i use ddns.net domain name. i’ll look at this asap and be back if needed !
thx
I added ServerName localhost to /etc/apache2/apache2.conf got past this.