To fix this issue, follow the simple guide below: If you’re using an older version of Outlook, the ‘Logon network security’ setting in the Microsoft Exchange dialog box may be set to a value other than Anonymous Authentication. Solution 2: Set the ‘Logon Network Security’ Setting to Anonymous Authentication

Close Control Panel and restart your PC.

Click on “Remove” to delete them from your PC.

Search for saved logins that have the word Outlook in their names and select each one of them to display more options.

In the right pane, look for the link that says “Credentials Manager” and select it.

Once you open it, search for “User Accounts”, and open the link.

Press the Windows logo key on your keyboard and look for “Control Panel”.

Start by clearing your cached passwords using the Control Panel. To resolve this problem, here are a few workarounds that you can try. How to Stop Outlook From Continually Prompting for a User’s Password

Your profile could be corrupted due to a malware attack.

Your profile could be configured in such a way that it needs to authenticate your credentials every time you send an email.

If you have recently updated or upgraded your OS, your new settings might be triggering the issue.

There is likely to be a problem with your Outlook app’s settings.

Here are some of the possible reasons that could lead Outlook to keep asking for your password:

Outlook 2019 profile keeps getting corrupted