Hi @默 齐
Welcome to our forum! As this is a public forum, please be aware of your personal privacy information. I have removed it.
Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client.
For better research, I would like to know what type of outlook.com account you are added to the Outlook client (POP/IMAP/Exchange)?
According to my tests, you need to configure both accounts as Exchange accounts for the calendar to appear in the Outlook client at the same time. Please follow the steps in the article to add an account directly. After the addition is successful, you need to restart the client to take effect.
In addition, if the Exchange account is configured and still cannot be synchronized, it may be related to your Outlook.com account. It's suggested that you could post your case in dedicated forum for Outlook.com for more professional advice.
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