Troubleshooting/Outlook Repeatedly Prompts for Login

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Microsoft Outlook Repeatedly Prompts for Login Password and Never Connects

My problem with Microsoft Outlook is apparently not uncommon: being unable to create a profile and complete the setup; unable to establish a connection; and Outlook repeatedly requests a password but couldn't complete a login.

The email server was Microsoft's own; the email client was Outlook 2016; I have a Microsoft Account and a subscription to Office 365. I have used Outlook trouble-free for years (on a different computer), so the behavior was both unusual and frustrating. Fortunately I had no problem accessing my email using Microsoft Mail, or in a web browser. But that also proved that the user-name and password pair was valid, even though it was not accepted when using Outlook.

The cause for my specific problem involved the two-step verification selection in my Microsoft Account. Even if that is not the same for you, maybe there will be some useful information on this page or in the links below.


What Changed?

If a process did work and now has a problem it is worth asking - what changed? In my case, several things as follows:-

  • I set up a new desktop computer with Windows 10 to replace an aging laptop using Windows 7.
  • I changed the password for my Microsoft Account, which is also (by default) used as the login on a Windows 10 computer.
  • I had been testing several different VPN services and since I noticed that Office 365 (and mail from may not update when a VPN connection is active ensured that the VPN was off (not connected) while trying to fix Outlook.

I have another laptop which remained unchanged, however it also started requesting passwords for Outlook and would not connect, send, receive or update email.

I now know that something else was changed but as it seemed insignificant I made no note of it at the time:- when updating my Microsoft Account I also turned on 'two-step verification', as recommended to protect my account settings and reduce the risk of identity theft.

Possible Solutions

I tried these steps first.

Solutions for Outlook repeatedly requesting a password

Apparently this is a common problem[1]. Some people blame specific Updates. Others suggest Registry keys which can be added to stop it. I tried many of those 'solutions' with no success. I concluded that if Microsoft Outlook keeps requesting a password that is a symptom of an underlying problem, not the problem itself.

Repaired Office 365

It seemed reasonable to check that there was nothing wrong with the installation of Office 365 including Outlook. However, the behaviour did not change after repairing the installation.

Use the Microsoft Support and Recovery Assistant for Office 365

This tool[2] is generally quite useful but failed to identify or solve the issues I had with Outlook. On some attempts it produced an error message:

"We're sorry we couldn't help you because of a service issue (Service Status=Unauthorised)."

After suggesting "Please contact Microsoft Office 365 Support" the list of faults included Autodiscover[3]. Yet that should have been fixed by one of the recommended Registry changes which had been implemented.

Disable IPv6

Some people suggested that Outlook may have difficulties authenticating if the network adapter is using IP version 6. The 'solution' is to disable IPv6 thus forcing the network to use the older IP version 4. So I did disable IPv6 but the problem was not solved.

IPv6 is integral to Windows operating systems and disabling it is not recommended and should not be necessary[4]. (After solving the real issue Outlook is working fine and since I 're-enabled' IPv6 has continued to function properly.)

Changing Credentials

The Windows 10 operating system includes a Credential Manager[5] which stores user-name / password pairs in a 'vault'. Some online passwords are stored and also some used by Windows applications. Apparently if you change a password online, occasionally the locally stored credentials are not updated and if Windows tries to use them the login will fail. Removing or editing Credentials made no difference.

Create new Profile in Outlook

As my installation of Office 365 including Outlook was new I didn't have a profile but I did attempt to create one - multiple times. If the connection could not be completed then the profile would not save. I tried automatically connecting through Office 365; a POP3 connection; and an IMAP connection, specifying different mail servers (Microsoft has a list and has some information about servers in the sync settings), each with the recommended ports and encryption protocols. None of the combinations worked. Each time a combination was tested the Error Report included messages like this:

"Log onto incoming mail server (POP3): Your email server rejected your user name. Verify your user name for this account in Account Settings. The server responded: -ERR Command is not valid in this state."

The user-name for an email account is the full email address like I was using the correct username and could access email on my phone, through a webpage or using Microsoft Mail. So the error message didn't make sense.

Changed my password

Since my problems occurred after I changed my password I decided to change it again and check that the new password worked correctly with my Microsoft Account, a direct login to using a web browser, and a login through Microsoft Mail. I also checked that the stored credentials were updated (in Credential Manager). And I attempted to create a new Outlook profile knowing for certain that the username and password were correct. But, as before, Outlook just kept requesting the password...

What Worked

The solution was to use an App password generated from my Microsoft Account instead of my regular password.

I stumbled on this solution in a Forum post email will not setup in Outlook 2016[6] and am both grateful to the original author and annoyed because none of the Microsoft 'solutions' includes an obvious diagnostic question:

In your Microsoft Account have you selected two-step verification?

Apparently, if two-step verification has been selected then Apps which are not capable of supporting the two-step process require a code. A new code is required for each App.

I think of an 'App' as being like an App on a smart phone, or a small application which can be installed from the App Store. I would not have called Microsoft Outlook for a PC an 'App' - traditionally it has been described as a 'Software Application'. Obviously I'm wrong! In Microsoft-speak, Outlook 2016 (and related versions) is an App and it cannot handle two-step verification and therefore needs a code (an App password) instead of a (normal) password.

The magic thing is, when I created a new profile in Outlook and used the code instead of a password, I did not need to manually setup the connection details - it worked automatically (that's what Autodiscover is supposed to do) and within moments my profile was saved, email started flowing into my inbox, and Outlook behaved as expected. It is also now using Outlook 365!


More Detail

  1. If you have a Microsoft Account, log in at or
  2. From the menu Menu select Security
  3. Below the Security Basics is a link to more security options
    More Options
  4. The page heading Additional security options is followed by an option to select Two-step verification:-
    Two Step verification option
    If you have a problem with Microsoft Outlook - not connecting, not updating, repeatedly requesting a password, etc. - try turning Two-step verification Off.
  5. Alternatively, and if you want to keep Two-step verification turned On, then look at the section headed App passwords
    The statement "Some apps and devices (such as Xbox 360, Windows Phone, or mail apps on your other devices) don't support security codes for two-step verification. In these cases, you need to create an app password to sign in." is also misleading - I underlined the word 'other' because it implies that there should be no need for an app password on the device you are using, the computer with Windows 10, Office 365 and Microsoft Outlook installed.
  6. The link Learn more about app passwords. opens an article Using app passwords with apps that don't support two-step verification which applies to your Microsoft Account and "apps or older devices (like Windows Phone 8 and Xbox 360) that don't support two-step verification." No mention of Microsoft Outlook 2016 on a PC!
  7. At this stage you can create an app password and use it for Outlook (or other unsupported application).
    The password looks like this: ymsretkuabnhpf
  8. When you create a new profile in Outlook use the App password instead of your normal Microsoft Account password.

I wish you every success!


Notes and References
  1. There are many articles about how to fix issues with Outlook. This one is quite useful: How to troubleshoot and fix common problems in Outlook from Windows Central at
  2. To Fix Outlook and Office 365 problems with Microsoft Support and Recovery Assistant for Office 365 download and run the tool from here:
  3. Before Microsoft implemented Autodiscover each email profile had to be configured manually. Now it is possible to enter the email address and a client such as Outlook will automatically discover the email server (or endpoint) and appropriate settings for the configuration. This article: Outlook 2016 Implementation of Autodiscover applies to Outlook 2016 and Outlook 2019
  4. Notes re IPv6
    1. The simplest way to 'disable' IPv6 is to deselect the item in the properties dialog for the network adapter. It will then look similar to this:-
      Network Adapter setting for IPv6
    2. However, note this: "Office 365 supports both IPv6 and IPv4; however, not all Office 365 features are fully enabled with IPv6. This means that you must use both IPv4 and IPv6 to connect to Office 365."
      This statement comes from the Microsoft document IPv6 support in Office 365 services dated ‎10‎/‎10‎/‎2018. The link is here:
    3. A more complete description of IPv6 in Windows is outlined in the document Guidance for configuring IPv6 in Windows for advanced users by Microsoft at
  5. To access the Credential Manager open the Control Panel and search using the word Credential. The Credential Manager enables you to manage Web Credentials and Windows Credentials.
  6. The solution that I have explained here was posted on the website on October 28, 2015 under the heading email will not setup in Outlook 2016. The problem matched my own:-
     - I have Windows 10, Office 365 and Outlook 2016.
     - Every attempt to setup my email address, automatic and manual, has failed.
      - The email works online only. It will not setup in Outlook 2016.
    The answer posted by Ernesto Barajas refers to MSN email but the concept works for email. The link is here: