Hello,
Please complete these steps on a computer, not on a smartphone or tablet.
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First, go to https://www.outlook.com and sign in.
Click the gear icon in the top right corner to open Settings.
Under Mail, review the following areas:
Rules
If any rules are listed, delete all of them.
Conditional formatting
If anything is set up there, delete it.
Forwarding and IMAP
If you see any entries or settings you did not create, remove them. Turn off POP and IMAP.
Junk
Review Safe sender and blocked list. If you don't recognize any, remove them.
Sweep
Make sure nothing is set up t here either.