SMTP configuration without SSL

Hello,
I have a mailrelay in my LAN where corteza is installed and it works without authentication and without SSL
I have configured it in my .env file.

SMTP_HOST=192.168.0.10:25

If I try to send mail with corteza I receive the following error:

execution failed: could not send email: x509: cannot validate certificate for 192.168.0.10 because it doesn’t contain any IP SANs

And from mailrelay logs I receive:

Jun 30 17:13:14 mailrelay postfix/smtpd[7141]: connect from dockerlan-test.sit.local[172.16.10.73]
Jun 30 17:13:14 mailrelay postfix/smtpd[7141]: SSL_accept error from dockerlan-test.sit.local[172.16.10.73]: -1
Jun 30 17:13:14 mailrelay postfix/smtpd[7141]: warning: TLS library problem: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate:…/ssl/record/rec_layer_s3.c:1528:SSL alert number 42:
Jun 30 17:13:14 mailrelay postfix/smtpd[7141]: lost connection after STARTTLS from dockerlan-test.sit.local[172.16.10.73]
Jun 30 17:13:14 mailrelay postfix/smtpd[7141]: disconnect from dockerlan-test.sit.local[172.16.10.73] ehlo=1 starttls=0/1 commands=1/2

It seems to me that corteza is using SSL

How can it be configured not to use SSL?

Thank
Nicola

This does not look an issue inside Corteza. But not 100% sure.

Is this postfix functional? Can you use it for other things?

Yes is the relay I use for example to let printers send mail. Of corse it accepts mail only from enabled IP but the IP of the docker host is enabled (172.16.10.73)

I have tried with telnet on the same corteza docker host and it works:

root@mailrelay:/home/comune# telnet mailrelay.sit.local 25
Trying 192.168.0.10...
Connected to mailrelay.sit.local.
Escape character is '^]'.
220 mailrelay.comune.sesto-fiorentino.fi.it ESMTP Postfix (Ubuntu)
HELO corteza
250 mailrelay.comune.sesto-fiorentino.fi.it
MAIL FROM: corteza@mydomain.it
250 2.1.0 Ok
RCPT TO: mymail@mydomain.it
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Subject: Test mail

Is there anybody out there?,
.
250 2.0.0 Ok: queued as 2C7B4F002CF

Try with

SMTP_TLS_INSECURE=true