Hi,
From a description, you have emails sent to your Outlook.com account forwarded to the other email account of yours, correct? How do you achieve this? Did you do it via setting a forwarding rule?
Does this issue happen in Outlook desktop application or in Outlook.com web mail app?
>>a large number of my regular contacts and email threads are getting filtered by Outlook
If possible, please try to add these regular contacts to your safe senders list and then see whether this issue continues.
In addition, since this forum is for questions and feedback related to Microsoft Outlook desktop application, if the issue happens in Outlook.com web mail app, I'd recommend you post a new question to the dedicated forum for Outlook.com to get further assistance:
https://answers.microsoft.com/en-us/outlook_com/forum
If I've misunderstood something, please feel free to let me know.
Regards,
Steve Fan
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