I spent a bunch of time last night trying to configure mono correctly based on what I thought was needed. I have mono-complete installed, but it didn't seem to make any difference.
This morning I tried one last thing to verify that the account itself was working. Since I'm using yahoo mail, I need an app specific password. I had one that I tested weeks ago and was working using openssl but I decided to request a new one to start fresh. With this new password, I followed some examples of manually sending messages. The basic flow is:
openssl s_client -crlf -connect smtp.mail.yahoo.com:465
ehlo localhost
auth login
<base64 encoded email address>
<base64 encoded app specific password>
mail from: <[email protected]>
rcpt to: <[email protected]>
data
this is a test email
.
quit
This worked every time. I sent several messages and it always worked. I then tried using the same settings in HG and it failed several times. There was a red herring in the log indicating an error with the script since there was no reason for the error listed in mono output. I then tried switching to 587 as a last ditch effort and it worked. I don't know why, but 465 used to work and 587 did not but now it's the other way around.
I will finish my RPi SD card setup guide over the next few days but it appears that some combination of mono-complete, switching ports, and requesting another app specific password has currently gotten my setup working again.