Hi Cynthia,
To further check on this, can you confirm if the account was recently added to Outlook. If so, please let me know how the account is configured.
If the account is set up as IMAP, this is normal behavior because IMAP only syncs email and does not support calendars. Outlook calendars will only sync if the email service supports and is configured as Exchange.
Before re-adding the account, it’s important to confirm that the email provider actually supports Exchange connectivity. If the provider does not offer Exchange, then calendar syncing in Outlook will not be available and only email can be synced.