Office 365, Email, Exchange, OWA, 'No Match Found' error while sending to multiple recipients

I'm getting a 'No Match Found' error when attempting to send to multiple recipients in the Exchange OWA.

The Exchange Outlook Web App uses semicolons(;) instead of commas(,) in between multiple email addresses when sending. Try entering semicolons and then attempt to send the message again.

New Outlook in Exchange Online eats the commas and doesn't cause this error. 

Keywords:Exchange OWA Webmail multiple recipients no match found   Doc ID:48034
Owner:Office 3.Group:University of Illinois Technology Services
Created:2015-03-03 15:21 CDTUpdated:2019-03-28 09:31 CDT
Sites:University of Illinois Technology Services
Feedback:  8   5