First of all, I apologize for not being very good at development and code.
In order to get more accurate development help and advice, I added the Exchange server development tag for your thread.
Here are some of my thoughts on whether Exchange Server is needed in your question:
1.How can get Exchange Server , is it mandatory for the X-AnchorMailBox Implementation?
Based on the information in the code page that you provided, it appears that services are being developed for Mailbox for Exchange online. Are you currently using the Graph API?
If this is the case, you should not need Exchange Server and EWS-related parameters.
In addition, according to my search, X-AnchorMailBox is used to lock the specified mailbox, and its value is set to the SMTP address of the targeted mailbox user.
Therefore, exchange server is not mandatory for the X-AnchorMailBox header.
2.Can you please help to get rid of Autodiscover Response as 600(Invalid Request) Issue.
Entering from the above URL and the page response returns "600 Invalid Request", which means that Autodiscover is working fine from the server side, which is the expected page.
3.How can we check and fetch Configured UserSettings
For services that Microsoft 365, I recommend that you use the Graph API to get information about users.
For specific commands, please refer to this link：Get a user - Microsoft Graph v1.0 | Microsoft Learn
Hope the above suggestions are helpful to you!
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