Under global on the MTA tab the authentication box is checked.
Under servers on the MTA tab the authentication box is checkes.
Under domains GAL is set to internal.
I assume this means that auth is enabled.
Restarted postfix via
/opt/zimbra/bin postfix stop
/opt/zimbra/bin postfix start
I get a prompt for a password from the client the first time I try to send, thereafter it just refuses to send.
This could be the problem we've had with zmtlsctl in the past - are you running in http mode or https mode? Make sure the contents of /opt/zimbra/conf/cyrus-sasl/etc/saslauthd.conf match the mode (eg, if you're in http mode, make sure the URL doesn't read https)
/opt/zimbra/conf does not contain a cyrus-sasl directory.
I found saslauthd.conf in /opt/zimbra/cyrus-sasl-2.1.21.ZIMBRA/etc/saslauthd.conf
it said the zimbra url was https so I changed it to match my useage which is http.
The first line was
zimbra_url: https://bruin.southofdallas.com/service/soap which I changed to http (since I'm using http not https). I'll see how that works.