Not Receiving Outlook Group Email Notification

Hello, I have a very strange issue that is happening. We created a form using Gravity Forms and are using WP Mail for SMTP. We have notifications set up to go to the admin, student and bursar group. We are receiving the notifications without any issues to the admin and student email accounts. However, we are not receiving the notifications to the group email account (created in Outlook) if the group has more than one person in it, however we do receive the notification if the group only has one person in the group. Weird right? Here’s where it get’s even more strange. If we input a group email that was created over a year ago that has more than one person in it, it is sending correctly as it should. Freaking weird! We’ve tried working with MS/Exchange/Azure Support to no avail. I know this isn’t a WordPress issue but I wanted to see if there was anyone who has experienced this same issue and can offer some guidance. Thank so much!