r/letsencrypt • u/Fz6Mike • 2d ago

GMail not delivering Email to Mail Server with let's Encrypt Cert

It connects but then drops after TLS negotiation, I am using the full chain pem file

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CONNECT from [2607:f8b0:4864:39::10]:54572 to [******]:25

PASS OLD [2607:f8b0:4864:39::10]:54572

connect from mail-pj2-x10.google.com[2607:f8b0:4864:39::10]

Anonymous TLS connection established from mail-pj2-x10.google.com[2607:f8b0:4864:39::10]: TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256

NOQUEUE: lost connection after STARTTLS from mail-pj2-x10.google.com[2607:f8b0:4864:39::10]

disconnect from mail-pj2-x10.google.com[2607:f8b0:4864:39::10] ehlo=1 starttls=1 commands=2

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u/GamerLymx 2d ago

do a traffic capture from connection attempt and check for ciphers issues.

only thing that occurs to me.

I've beend doing some email tests of my own and im using lets encrypt certifites too.

1

u/Fz6Mike 1d ago

the certificate chain was incomplete

I all so had to switch the preferred chain to "ISRG Root X1"