Exchange 2016: Seeing different mailbox GUID formats in Outlook profile

BYS used Ask the Experts™
When I look at the Outlook profile for mailboxes on Exchange 2016, different mailboxes have the GUID in different formats. Has anyone seen this before and know why they are different (for different mailboxes)?

Format 1:

Format 2:

outlook screenshot
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Format 1: Outlook anywhere using MAPI over Http.
Format 2: Outlook anywhere regular.

Check way they are connecting using the "outlook icon next to the hour", press ctrl+Right Mouse  and select "Outlook connection Status"
In there you can see how are the client's connecting to the server

Here's an article for 2013 that applies also to 2016:


Thank you Jose! I had MAPI/HTTP disabled on one of the mailboxes which is why I was seeing the RPC/HTTP format. Thanks again!

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