More loggging...

This is logging that wasn't getting caught before.

docs/courier-to-mailman3.md

@@ -45,3 +45,6 @@ This is our current version trying to communicate between courier and mailman3.
 * Oh man `To` vs `'To'`
 * Progress...  But getting, "line too long" this seems like I need the 
   replace that I had before.
+* OK, that's progress...  But not sure what, failing to get logs that are
+  useful.
+* 

source/courier-to-mailman3.py

@@ -64,6 +64,9 @@ try:
             content
         )
     except smtplib.SMTPResponseException as e:
+        logger.error('lmtp error on send')
+        logger.exception('Got exception Traceback:')
+        logger.error('lmtp failed errorno: %s, message: %s', e.errno, e.strerror)
         if 400 <= e.smtp_code < 500:
             exit(111)
         # otherwise, it's either a 5xx aka permanent error or something else