Add a Service Credential pop-up in Outlook Critical issue

Question

A new Microsoft Credential Pop-Up labeled "Add Service" is preventing users from connecting to our On-Prem exchange server.

We have On-Prem Microsoft Exchange 2019, and also have Office 365 licenses for each client machine. The "Add a Service" prompts come up non-stop. Most of the time the box is pre-filled with their local domain creds.

I have been through all the fixes I can see on the answers Microsoft forums but most end with the issue unresolved. We have tried:

1. Remove old/unused devices the portal under apps and devices
2. Removed services in portal like Microsoft Power Automate Free, Microsoft Teams Exploratory however many of the user don't even have these services assigned.
3. Updated office and windows on the affected machines
4. Ran the Microsoft support and recovery assistant for Outlook "SetupProd_AuthChk.exe"
5. Tried several recommended registry updates

This started happening about 4 weeks ago and is causing huge issues, there must be a solution. Critical and often time sensitive email messages are being missed or not seen for hours or in some cases days.

For a temporary work around I some people who have the issue more often log into outlook web access on the exchange server.

Answer 1

It may not be the answer for all but I tried unchecking all the checkboxes under connected experiences. if all is unchecked it will remove the connected services under the user information in the office account which in turn prevents the add a service pop-up from showing and your Outlook will never lose connection again

• Click on File
• Under File, click on Office Account
• Under Office and Account, click on Manage settings
• pop-up windows show, look for connected Experiences, and uncheck all checked boxes

Hope it works

Answer 2

Hi @Carl Cobon ,

Good day! 

Thank you for posting to Microsoft Community! 

Based on your description, I understand you got a constant "Add a Service" popup in Outlook. You have already tried many common solutions, but it did not work.

Please kindly delete the account and re-add it in Control Panel as screenshot below to see if it works.

Also, you could try to delete the Outlook Profile and Create an Outlook profile - Microsoft Support.

However, it is most likely related to the problem on the backend side. If the above does not work for some reason, to check further and help you more efficiently, it is suggested to raise a ticket to contact our technical team via Microsoft 365 admin page Get support - Microsoft 365 admin | Microsoft Learn. Since we are from the community team, and we don't have that permission and resources to check this account issue from the backend side.

If the answer is helpful, please click "Accept Answer" and kindly upvote it.

Answer 3

I believe it is related to the number devices signed into your Office365 apps (limit is 5 devices per license). The following has worked for me:

• Go to https://portal.office.com/account and sign in
• Under Office apps & devices, click View apps & devices
• Sign out of every device that is no longer being used until you get to 5 or fewer devices
• Reboot your PC

Answer 4

The problem has been annoying individual users since 2023, without there seeming to be a solution or a description of the cause. I now have (as of June 2025) several cases where the problem occurs with Outlook classic (2016-2024) and the usual fixes do not help (or only for one day). Even crazier: If Fiddler is running for recording (the tool creates a proxy for the Internet connection), the pop-up no longer occurs. See also the summary in the blog post linked below.

Outlook Classic issue: Shows suddenly an "Add a service" popup and ask for credentials (June 2025)

Answer 5

✅ Confirmed Fix: Disabling Connected Experiences Resolved Outlook “Add a Service” Pop-Up

I’d like to confirm that disabling Connected Experiences in Office fully resolved the persistent “Add a Service” credential pop-up in Outlook for me.

Background:

Windows 11 + Microsoft 365 (classic Outlook)

Multiple personal accounts, no active work/school accounts

Issue triggered when editing shared calendar events

Pop-up: “We couldn't find a work or school account with that email address”

Outlook also showed “Need Password” banner intermittently

What Worked:

After extensive troubleshooting (registry cleanup, removing old credentials, deleting profiles, etc.), the final fix was:

Open any Office app (e.g., Word)

Go to File → Account → Manage Settings

Uncheck all boxes under “Connected Experiences”

No restart was needed. The fix was immediate. Calendar interactions became noticeably faster and smoother—an unexpected but welcome performance boost.

Developer’s Note:

As a software developer, I suspect the Connected Experiences subsystem is making undocumented background calls tied to decommissioned accounts. The performance degradation was silent and significant.