Outlook prompting for credentials while migrating from 2016 to 2019

Question

I have a 2016 dag that I'm trying to migrate to a new pair of 2019 servers. I followed the Exchange deployment assistant. If I leave owa.domain.local pointed to the old 2016 exchange server(s), Outlook works perfectly fine. Autodiscover comes back clean in the outlook tests. I switch the OWA cname over to the 2019 servers and I constantly get prompted for credentials.

My virtual directory URL's are all correct. OWA works fine. Mailboxes can be on 2016 or 2019 databases and work.

I've been reading threads and comparing things but cannot seem to find what might be causing this issue.

Answer 1

I figured it out. It was the Alternate Service Account credentials as the servers are behind a load balancer.

https://learn.microsoft.com/en-us/Exchange/architecture/client-access/kerberos-auth-for-load-balanced-client-access?redirectedfrom=MSDN&view=exchserver-2019I had to update the new servers to use the service account of the other 2016 servers:

cd 'C:\Program Files\Microsoft\Exchange Server\V15\Scripts' .\RollAlternateServiceAccountPassword.ps1 -ToSpecificServer exchange2019-1.mydomain.com -CopyFrom Exchange2016-1.mydomain.com .\RollAlternateServiceAccountPassword.ps1 -ToSpecificServer exchange2019-2.mydomain.com -CopyFrom Exchange2016-1.mydomain.com

Answer 2

Hello @Trent,

Based on my experience, I suggest you try the following methods:

1.Since we change the configuration on server side, so I suggest to create a new Outlook profile to force updating the configuration:

Create an Outlook profile

https://support.office.com/en-us/article/create-an-outlook-profile-f544c1ba-3352-4b3b-be0b-8d42a540459d?ui=en-US&rs=en-US&ad=US

2.In general, changing the OWA URL will not infect on Outlook client. So I need to know the internal DNS configuration, such as the A record/CNAME record.

3.Please Run Test Email Configuration in Outlook client

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1. In Outlook , hold Ctrl key and right click the Outlook icon in the system tray.
2. Select Test E-mail AutoConfiguration.
3. Only select Use AutoDiscover and click Test.
4. Please take a screenshot of the Log and result tab, save it as a .jpg files and upload the images in our forum directly.

 4.Check your SSL certificate:

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1.Use IIS Manager to go to your Exchange 2019 server to confirm that the SSL certificate is installed.

2.Check in the binding whether the certificate has been assigned to the HTTPS site.

3.Make sure that all required domain names are included in the SSL certificate, such as 'autodiscover.<yourdomain>' and 'mail.<yourdomain>'.

Internet Information Services (IIS) needs to be restarted after changing settings to ensure all new settings are applied. This can be done by running the command "iisreset" in Command Prompt or PowerShell.