Hi @Debo
Thank you for posting your question in the Microsoft Q&A forum.
Based on description, look like your calendar unexpected disappeared.
First, I will need more information so I can assist you better.
May I know which Outlook version are you using (New Outlook, Classic Outlook)?
Please try sign in Outlook web to see if your calendar shows up there.
FYI, Outlook cannot sync calendars from POP and IMAP accounts.
Please clarify if the calendar has ever appeared in Outlook before, or it never appeared in Outlook?
You can find more details at Sync basics - what you can and cannot sync - Microsoft Support
I'm looking forward for your reply.
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