Hi @Beth Nolan Conners ,
Welcome to our forum!
Are you sending emails to Outlook.com groups?
If so, based on my research on the error you provided, this is unfortunately a known issue. Microsoft is in fact aware of this and working on a fix. Right now, the only thing we can do is to wait for the fix to be rolled out. I will post back as soon as the issue is updated.
More information: https://portal.office.com/ServiceStatus
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