Hello @Saied Elshorbagi,
Thank you for reaching out to the Q&A forum!
I see that the Q&A Assistance provided the necessary troubleshooting steps. I will add additional details and clarifications to each solution so you can follow them more easily.
1.Clear Cached Passwords from Credential Manager:
This is the most frequent cause of the looping prompt. Your computer stores your Outlook password securely, but if that stored data becomes corrupted, Outlook will repeatedly fail to authenticate, no matter what you type.
- You need to close Outlook completely, then open the Control Panel. You can do this by searching for "Control Panel" in the Windows Start menu.
- In the Control Panel, you change the "View by" option to Large icons or Small icons for easier navigation.
- You click on Credential Manager and select Windows Credentials.
- Under the "Generic Credentials" section, look for any entries that mention "Outlook," "Microsoft Office," or your email address. They will often have a format like MicrosoftOffice16_Data:SSPI:******@address.com.
- You click on each relevant entry to expand it, and then click Remove. Confirm the removal when prompted. After that, you restart your computer.
Note: Especially when you open Outlook again, you will be prompted to enter your password again. Be sure to check the box for "Remember my credentials" or "Remember password" to prevent this from happening again.
2.Create a New Outlook Profile:
A corrupted Outlook profile can cause a variety of authentication issues. Creating a new, clean profile is a great way to isolate if the issue lies with your profile data.
- You can lose Outlook, open the Control Panel, and search for Mail. (It may be labeled "Mail (Microsoft Outlook)").
- In the Mail Setup dialog box, you click on Show Profiles.
- Click Add and give your new profile a name (e.g., "New Outlook Profile"). You need to follow the prompts to add your email account to this new profile.
- Once the account is set up, go back to the "Mail" window and set the new profile as the default by selecting "Always use this profile" and choosing the new profile from the dropdown list.
- You click OK and start Outlook to see if you can log in without the looping prompt.
3.Repair New Outlook:
Additionally, you can try repairing the Outlook app by following these steps:
- You can go to Settings => Apps => Installed apps. Then, you locate Outlook (New) and select Advanced options
- You need to scroll down to repair the app.
If Repair does not resolve the issue, you can also try selecting Uninstall and then reinstall New Outlook.
If the issue still persists after trying all the steps above, please reconfirm this point:
I noticed that your post is tagged as “Business.” Could you please confirm whether you are using a work/school (organization) account, or a personal Microsoft account such as outlook.com / hotmail.com?
Once I have this information, I will be able to guide you on how to reach the appropriate technical support channel if needed.
I hope you can understand that, as a forum moderator, I don’t have access to internal backend. At this time, the only thing I can do is research and share publicly available information to assist you as accurately as possible within the scope of this forum.
Looking forward to hearing from you!
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