Hi Timothy,
I notice that the issue only happens to one specific user. Please do the following steps to narrow down the issue:
1. Logon Remote Desktop Server with a working user account, setup this problematic user's mailbox in Outlook 2013. Verify if the Out of Office setting can be configured.
2. On this problematic user's Remote connection, access the mailbox in OWA, check if this user can configured Out of Office in web.
3. Create a new Outlook Profile for this user to have a try: Control Panel > Mail > Show Profiles > Add, then setup this problematic account in new profile. Set "When starting Microsoft Outlook, use this profile: Prompt for a profile to
be used". Use this new profile and confirm if the issue can be fixed.
Best Regards,
Winnie Liang
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