To get rid of calendar invite spam in Microsoft Calendar (Outlook), disable the automatic meeting request process. This will prevent the meeting from appearing on your Microsoft Calendar in the first place. You can then either delete the spam email in your inbox or mark it as spam. Note that after changing your calendar settings, none of your legitimate meeting request will get approved until you accept the meeting yourself or someone else who has access to your calendar accepts the meeting on your behalf.
1. Open the Outlook app
In Outlook, go to File and then “Options.”
select “Mail” from the Options menu and Scroll down to the “Tracking” field
Under “Tracking,” deselect the option that says, “Automatically process meeting requests and responses to meeting requests and polls.”
Once this feature is disabled, look for the spam email with the meeting and block it.
Right-click on the email –> Junk –> Block Sender
Go to your calendar and Delete the spam meeting as well
After you block the sender, the email will be automatically sent to the Junk Folder