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Hi, and thanks for reaching out. My name is Miguel O., Sorry to hear you're experiencing this issue!
If you see Error 400 when trying to sign in repeatedly with your Microsoft account password, try to use a different sign in method, such as a code from Authenticator or text message, a passkey on a trusted device, or Windows Hello.
To prevent the issue from happening again, make your account more secure by going passwordless.
Many users had been able to solve this issue by logging in using another method as using a code sent to their email.
If you have any trouble following any steps or the issue persists, let me know!
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