There is a function in O365 Outlook to send Email Reminder to all attendees, in which Microsoft will send an reminder email to all attendees on your behalf:
My question is whether Microsoft can still send out the email when the account is no longer valid, say it has been shut down by the administrator?
Looking forward to your valuable advice!
Thank you so much~
Depends on what you mean by "shut down". If the mailbox has been deleted, no. If the mailbox still exists, albeit in a disabled state, then yes.