Hi Kani,
Greetings! Thank you for posting on Microsoft Community!
For your concerned issue, Microsoft is aware of this problem and are working on filtering those spam meeting invitations out.
There are 2 workarounds for this issue currently:
- Create Outlook inbox rule:
- Open Outlook.com or outlook.office.com, navigate to Setting
- Select View all Outlook settings.
- Under Mail, click Rules.
- Click Add Rules.
- Under Add a condition, select From/Sender address includes and input the spammers' addresses. You may also use a different condition that is more appropriate. Also, you may set exception.
- Under Add an action, select Delete.
If you are using a Microsoft 365 business account, please let your Exchange Admin setup mail flow or EOP rules for spam filtering.
- Delete the spam meeting invites series, and ensure that you don't send the spammer a response.
We apologize that the permanent solution of this issue is still under investigation from Microsoft. You might want to provide feedback to Microsoft Uservoice.
Appreciated for your understanding and patience!
This is not a fix. I ended up having to delete your trash calendar.