Apple mail access to Argonne mail

Please see the following announcement from BIS:
Beginning on Friday, July 28, selective Mac device users began reporting issues in regards to using Mac Mail. New emails were not being received into their Inbox, but they are able to send new mail and read existing messages already in their Mac Mail client. Also, emails did appear when using Outlook for Mac or accessing the mailbox via the web at http://portal.office.com. Either of these options will serve as an effective workaround while BIS investigates the issue. At this time it appears the issue is affecting Mac Mail clients using the “EXCHANGE” setup only. Mac Mail users with an IMAP setup are not affected. Further details will be sent when information is available or resolution identified.