Add a Service Credential pop-up in Outlook Critical issue

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.