In our experiences with Office 365 and Listserv, getting the DMARC feature in Listserv enabled helped (mostly). That included tuning our SPF records. If you are in control of the problem Office 365 tenant, check your Exchange Online Protection filters. You may need to put exceptions there for Listserv mail. Andrew Bosch Infrastructure Engineer Evangelical Lutheran Church in America 8765 W. Higgins Road, Chicago, IL 60631 773-380-2492 [log in to unmask] ELCA.org -----Original Message----- From: LISTSERV Site Administrators' Forum <[log in to unmask]> On Behalf Of Andy Richter Sent: Thursday, April 11, 2019 3:15 PM To: [log in to unmask] Subject: O365 regularly blocking LISTSERV owner email addresses I am seeing several cases where Office 365 is automatically blocking email addresses associated with the "owner" addresses of some of our LISTSERV mailing lists, usually shortly after a legitimate email is distributed to the list members. So far, I have not been able to identify the likely cause of these blocks. Any suggestions? -- Andy Richter | Senior System Administrator | Information Technology | Vanderbilt University [log in to unmask] | phone 615.343.4518 | Did You Know? VUIT offers help, training, discounts and more at it.vanderbilt.edu ############################ To unsubscribe from the LSTSRV-L list: write to: mailto:[log in to unmask] or click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1 ############################ To unsubscribe from the LSTSRV-L list: write to: mailto:[log in to unmask] or click the following link: http://peach.ease.lsoft.com/scripts/wa-PEACH.exe?SUBED1=LSTSRV-L&A=1