I have just added a exchange 2013 server to my environment.  We are now in a coexisted 2007/2013 environment.  Mail flow is working fine for all clients(on and off the corporate network).  My issue is that when a users with a laptop with outlook 2010 or 2007 that have been migrated to the new 2013 server are off the corporate network or even via a vpn connection, They are continually prompted for credentials.  They have 3 options

1. Enter credentials and continue to be prompted until your fingers fall off.

2. Click "cancel" on the request and get prompted a few minutes later.  this will leave the "need password" notificationn in the status bar but mail comes and goes just fine.

3.Click the send receive tab and click the key button.  this tends to delay the prompt for around 10 min then comes back.  again with this option mail comes and goes just fine.

Please note: Outlook 2013 users are not affected. Additionally this is only affecting users that have been moved to the new 2013 server.  Users still on the 2007 server are not having any issues.

I suspect the prompt is for oab or public folder but am not sure how to troubleshoot further. Any help would be appreciated.

• Edited by Bill schloer Friday, August 21, 2015 5:40 PM

Hi Bill, 

Thank you for your question. 

By the issue, we could do the following test. 

1. Did the issue occur when the user is in the corporate?
2. Did the issue occur when the user is out of the corporate? 

Please make sure NTLM authentication is enabled on Exchange server side (include Exchange 2007 and Exchange 2013) and outlook side, then check if the issue persist. 

If there are any questions regarding this issue, please be free to let me know. 

Best Regard, 

Jim