Hi Courtney Crossan,
Thank you for using Microsoft products and posting in the community.
I realize that your email account may have been hacked and received a bounce letter from postmaster. Not only does this clutter your inbox, but it also creates confusion😠. I get into your skin and understand how you feel.
Let me explain: these bounce notifications usually occur when you send or forward an email to a non-existent address. I know it shouldn't be possible for you to manually perform this action yourself so that you can check if someone has changed your email forwarding settings and rules.
- Sign in to Outlook Web.
- Click the gear icon in the top right corner to enter the email settings.
- Go to Mail > Forwarding and make sure forwarding is turned on.
- Go to Mail > Rules and make sure that forwarding rules are configured.
I'm sure this can't be a forwarding process that you set up yourself, so disable it and delete any email addresses you don't recognize. And if your account settings were changed without your knowledge, it's likely that your account has been hacked. For the safety of your account, you should not take it lightly and always be wary of your hacked accounts. This is because if you keep sending or forwarding emails to an inactive address, the server can automatically determine that your email behavior is abnormal, which is exactly what hackers want to see😡!Therefore, you need to take steps to prevent your account from being compromised. I recommend verifying your account for sensitive information, such as the presence of alternative aliases or authentication methods. Please see: How to help keep your Microsoft account safe and secure - Microsoft Support
Right now, as soon as you remove email addresses (from hackers) that you don't recognize, you're completely blocking the forwarding behavior, which is by far the most important and effective thing for you!
If you suspect that your current device contains malware, we recommend backing up all important data and then running a full scan of your device with antivirus software.
Thank you for your patience and support. I hope the above information was helpful to you😊. Feel free to let me know how it goes by answering it below.
Best regards
Vivian - MSFT | Microsoft Community Support Specialist