• Community Support
  • USEnglish

  • Yet another TLS Handshake Failure Question - GMX and Yahoo not working

Hi together,

i have problems with sending mails to gmx. I always get a TLS handshake failure when sending mail.

I tested with other providers which work fine. Google, Vodafone work fine.

My setup is as following:

  • Mailcow on a dedicated VM behind NGINX Proxy Manager
  • All ports are forwarded to Mailcow
  • Copied the Certs (cert1.pem -> cert.pem and privkey1.pem -> key.pem) from NGINX to Mailcow and disabled Letsencrypt on Mailcow, restarted Mailcow
  • Certs are only for mail.mydomain.com, not autoconf .* or autodiscover.*

I tested my config with checktls.com Icon Secure Email

checktls.com Icon checktls.com
Secure Email
CheckTLSYour LOGO HereInternet email
but this is also showing me a TLS error:

Cert VALIDATION ERROR(S): unable to get local issuer certificate

Mailcow logs show me for example:

SSL_connect error to mta7.am0.yahoodns.net[67.195.204.72]:25: Connection timed out

I dont know how to debug further 🙁

      MrSliff Copied the Certs (cert1.pem -> cert.pem and privkey1.pem -> key.pem)

      The docs state, that you need to use “save the combined certificate (containing the certificate and intermediate CA/CA if any) to data/assets/ssl/cert.pem”
      docs.mailcow.email Icon Advanced SSL - mailcow: dockerized documentation

      docs.mailcow.email Icon docs.mailcow.email
      Advanced SSL - mailcow: dockerized documentation
      None
      docs.mailcow.email

      What you did is only copy the certificate itself, you should copy the fullchain.pem -> cert.pem…

        Have something to say?

        Join the community by quickly registering to participate in this discussion. We'd like to see you joining our great moo-community!

        Ah, damn i knew it. Sorry, will try again!

        No one is typing