We have three Exchange server. msexch1, msexch2, msexch3. msexch1 is currently offline. msexch1 and msexch have the CAS and MBX roles installed and are in a DAG. We moved all mailboxes from msexch1 to the other two servers. Since then we have users reporting that when they logon to owa they get a blank page. The resulting url is owa/auth.owa. The domain we use is exchange.ourdomain.com. The fqdn of each exchange server is msexch2.ourdomain.com, etc. We use round robin dns for our exchange servers, therefore we have two entries for exchange.ourdomain.com. For the purposes of this question lets say the ip of msexch2.ourdomain.com is 10.10.10.52 and msexch3.ourdomain.com is 10.10.10.53 and we have two entries in our dns for exchange.ourdomain.com, one for 10.10.10.52 and the other 10.10.10.53.

When a user experiences this issue I have found that when I ping exchange.ourdomain.com to determine which exchange server they are "connected" to; if I force them to use the other one they are then able to access owa just fine. For example, I have a user whom is getting a blank page after they logon to owa. I ping exchange.ourdomain.com which returns 10.10.10.52 for an ip address, which tells me they are connected to msexch2.ourdomain.com. When I enter in the url https://msexch3.ourdomain.com/owa to force them to logon using the other server, they are able to owa owa without any issues. When I use the url https://msexch2.ourdomain.com they receive a blank page after logon (as expected because this is the server they are trying to contact via dns exchange.ourdomain.com)

I have tried recreating both owa virtual directories which did nothing. I am at my wits end here and would greatly appreciate any assistance.

Hi,

According to your description, I understand that OWA get blank after move mailbox to another mailbox server, and you deploy DNS round robin in your environment.
If I misunderstand you concern, please do not hesitate to let me know.

It may be caused by OWA proxy cannot work correctly, please try below steps to double check:
1. Get a mailbox place in msexch3 and login OWA with https://msexch3.ourdomain.com/owa.
2. Get other mailbox place in msexch2 and login OWA with https://msexch3.ourdomain.com/owa.
If the steps 2 cannot proxy URL to https://msexch2.ourdomain.com/owa, it may be the key reason.

Please clarify the environment of your Exchange:
1. Which version are you used?
2. Check the authentication of OWA: Get-OwaVirtualDirectory | FL Identity,*URL*,*Auth*
OWA is configured to use integrated windows authentication on each virtual directory, and the external URL under is blank.
Also, please run below command to double check the health of Outlook Web App service:
Get-ServerHealth msexch3 |?{$_.AlertValue Eq Unhealth}

Thanks