Hu I've a strange problem with my #postfix #smtpd (I presume?) . Trying to send a mail trough it with #thunderbird , it fails with the error:

> Peer’s Certificate issuer is not recognized.

my cert is issued by Let's Encrypt and is not expired.

In postfix's logs I get this:

> smtpd[552582]: SSL_accept error from unknown[176.x.x.x]: -1
> smtpd[552582]: warning: TLS library problem: error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca:../ssl/record/rec_layer_s3.c:1571:SSL