09-20-2016 15:45:00.279 +0000 INFO ExecProcessor - message from "python /opt/splunk/etc/apps/TA-mailclient/bin/mail.py" Got credentials from endpoint - Username(firstname.lastname@example.org)
This unfortunately, is the only message I get from TA-mailclient, I don't see any mail going in the index, nor I know what made it fail to do so.
I'll add this in over the next week and test, and I'll release an update. It'll log as INFO. Should also include support for more special characters in the password field.
I've uploaded an update. This should be fixed now. All exceptions will now be handled in someway, and you should find login failures with :
index=internal sourcetype=splunkd component=ExecProcessor mail.py loglevel=INFO