Welcome to our forum!
Based on your description, it looks like you're experiencing an account security issue. Here are some steps you can take to protect your email account:
- Check for Malware: Run a full scan on your devices using trusted antivirus software.
- Review Account Activity: Look at your account’s recent activity to identify any suspicious logins or devices.
- Change Passwords on a Clean Device: If possible, use a different, secure device to change your password.
In addition, please refer to the tips in this document to strengthen the security of your account.
https://learn.microsoft.com/en-us/defender-office-365/responding-to-a-compromised-email-account.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.