jimhill10
I wanted to confirm my understanding of the situation. It appears that the bounce address has been changed to a different domain than the one emails are being sent from. In order to maintain DMARC compliance, it's important for the FROM, REPLY-TO, and BOUNCE addresses to have the same domain.
To ensure compliance, I suggest keeping the bounce address that matches your domain, setting up a forwarder to send the bounces to a non-O365 address, and configuring the bounce handling to use this non-O365 mailbox.