I have a workflow that reconciles time submitted on timesheets with vacation data from our payroll system and emails everyone who did not submit enough total time between the two of them during a given week.
This process has run for 2+ years including last Monday and today failed with the message:
ERROR Send Email 3:34 Execute failed: Error while communicating with the smtp server: com.sun.mail.smtp.SMTPSendFailedException: 550 5.7.607 Access denied, banned sending IP [my companies main domain]. To request removal from this list please visit https://sender.office.com/ and follow the directions. For more information please go to Remove yourself from the blocked senders list and address 5.7.511 Access denied errors - Office 365 | Microsoft Learn AS(1435) [DM6NAM10FT042.eop-nam10.prod.protection.outlook.com]
Note that “com.sun.mail.smtp” is NOT the SMTP server that I configured and am using in my workflow nodes.
.
Is this used by Knime under the hood?
Any advice on what is going on and why this might have started this week after 2+years of no issues.
Thanks,
Mike
===============
More Details
My list of users that needed to receive email notifications had only 15 members. On the first run it send the email to 7 members. When I reran the process for the remaining members, it send out 3 emails and then again failed with the same spam/phishing error from Office 355.
My organization uses the same SMTP Server for other email notifications and never had issues.
It seems my email or domain is now listed as a SPAM site in Microsoft Office 365. I followed the instructions and link and could not be delisted. I had to click on an escalation request.
I am still able so send emails from the same FROM email from my personal outlook account and via Knime on the VM that I use.