This! This is what is happening to me now. I posted here: Email set up - #6 by ZAFMike but this is my problem. When I enable Do not verify TLS certificate for port 25 it sends a test email successfully but then when I try to send an Invoice it says Failed to send. The email is critical as I send out many a day and now I am having to save them then upload them to my business email and send them out which is soooo much more time consuming.