Outlook is Prompting For Password to Connect to MS Exchange Server

One of the most annoying problems for Outlook users is, every time Outlook is prompting for password when connected to MS Exchange . In Outlook 2007, this problem is caused by a known bug but there is no known bug that can cause this problem in another version of MS Outlook. In this blog, we have explained some possible symptoms and cause for persistent MS Outlook prompt for password with their respective solution.

Why Outlook Asks For Your Password

When you connected Outlook to a Microsoft Exchange server, it setup a secure network to your email, calendar, contacts, and other mailbox information. To ensure security, Outlook uses an username and password authentication scheme.
This is how it works.

Credential Entry: When creating an Outlook profile, you enter your username and password. Windows Password Manager stores these credentials securely.

Authentication Protocol: Outlook establishes a connection to the Exchange server via an authentication mechanism such as Basic Authentication, NTLM, or Modern Authentication (OAuth 2.0). Your organization’s security settings and configuration determine the protocol you use.

Credential Verification: The authentication request is sent to the Exchange server, along with your credentials. It compares these credentials to its directory service (typically Active Directory) to authenticate your identity and access rights.

Secure Connection: If the login details are valid, the Exchange server permits access and establishes a secure connection. Outlook may now send and receive emails, manage calendars, and access more mailbox capabilities.

Fix Outlook is Prompting For Password to Connect to MS Exchange Server

Symptom 1:  MS Outlook is prompting for password when connected to MS Exchange 2013 mailbox for the first time.

Cause: MS outlook is connected to a mailbox residing on Office 365.

Solution: The password prompt dialog box also contains a checkbox for Outlook to remember credentials. Users can easily fix this problem by selecting the checkbox to force Outlook to remember their credentials and won’t get the password prompt dialog box until they change their password. If the problem is not resolved by the above-mentioned procedure then the Outlook password prompt issue is related to improper Global Catalog server registration. To resolve this issue, you need to remove the current service principal name registration and need to register them using the Global Catalog server.

Symptom 2: MS Outlook is prompting for a password when connected to MS Exchange repeatedly even after providing the information. Microsoft Internet Information Server (IIS)   may prompt for user name and password and you may get the error “401.1 Unauthorized: Logon failed ”when you provide the wrong credentials because of the inability to connect MS Outlook web access by using the IP address of the server.

Cause: The prompting issue can occur when the Exchange server rejects NTLM and LM and configured to accept only Microsoft Windows NT LAN Manager Version 2. MS Outlook client system is not configured with the same LAN authentication level.

Solution: Set the Client and Server to the same level by changing the LAN Manager Authentication Level. Check the Domain Controller and Domain Controller Policies by following below mentioned steps.

Note: This solution applies to Windows 2000.

Check the Settings on Domain Controller

• Click on Start, and then click on Administrative Tools
• Expand Local policies in Local Security settings

• Click on Security options and then note down the LAN Manager Authentication Level.

• Right click on LAN Manager Authentication Level and change the settings.

Check Domain controller Policies

• Click on Start, and then click on Administrative Tools
• Click on Domain Controller Policies and then expand Local Policies.
• Click on Security options and then note down the LAN Manager Authentication Level.

Set LAN Manager Authentication Level to “Send NTLMv2 response only”. Make sure that all computers in the domain have same authentication level, if you want to apply particular authentication level in your network.

You may need to manually configured group policies on the following clients because they are not affected by Windows 2000 Group Policy.

• Microsoft Windows 95
• Microsoft Windows 98
• Microsoft Windows Millennium Edition (Me)
• Microsoft Windows NT 4.0

Symptom 3: Outlook is prompting for password when connected to MS exchange after the password for your account is changed.

Cause: You have saved your credential before your password has been changed and the stored credential is not overwritten.

Note: This solution applies to MS Outlook 2010 and 2013.

Solution: Install the latest update for MS Outlook.

If you are unable to install the latest update then follow the below-mentioned steps to remove previously saved credentials.

• Click on Start and then click on Control Panel
• Click on Credential Manager
• Select the set of credentials that has outlook in the name and then click on the name.
• Click on Remove from Vault.

Symptom 4: MS Outlook continuously prompted for credential when attempting to create an Outlook profile. You may get the following error if you click on cancel.

Cause: The prompt for password issue occurs because Anonymous Authentication is not set as a value in Log on Network Security.

Solution: Change the Log on Network Security setting by following below mentioned steps.

• Open Control Panel
• Click on Mail and then Click on Show Profiles.

• Select your Outlook Profile and then Click on

• In Mail Setup Window, Click on Email Accounts

• In Account Setting tab, Select your profile id and then Click on Change

• In Change Account box, Click on More settings.

• Select Security tab in Microsoft exchange box.
• From Login network security, select Anonymous Authentication, click on Apply and then click on OK.

• Click on Next and then click on Finish.

Conclusion

In this Blog, we have discussed causes with their respective solution awhen Outlook repeatedly prompted for password. Fix the error: Outlook is prompting for password when connected to MS Exchange easily by following the steps explained above.