I've setup a new Exchange 2016 server.
The server was installed into an existing AD with an Exchange 2010 installation.
All worked well and the new server is operational.
Our firewall and DNS still points to the old server for Outlook Anywhere and is working for the mailboxes still on the old server.
As soon as a mailbox is migrated to the new server, the mailbox becomes inaccessible via Outlook Anywhere.
For example, trying to access the mailbox from OWA produces the following error:
A server configuration change is temporarily preventing access to your account. Please close all Web browser windows and try again in a few minutes. If the problem continues, contact your helpdesk.
Is there a way to have Outlook Anywhere working for mailboxes on both the old and new server via Outlook Anywhere (the same host name)?