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

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.