I tried setting up my Office Web Apps Server in my virtual environment on my domain controller to cut down on the number of the virtual machines. Later, I found out this was unsupported, so I rolled back to a previous snapshot of my domain controller machine and created a new VM just for the Office Web Apps Server. After I created the new server I needed to change the SharePoint WOPI binding to point to the new server. Here’s how I did it.
First, I ran the following PowerShell command from the SharePoint 2013 Management Shell.
Get-SPWOPIBinding -Server "dc.powder.ski" | Remove-SPWOPIBinding
This command fetches all the WOPI bindings associated with the Office Web Apps Server I originally created on the domain controller. Then, it removes them.
After removing the bindings, I registered the new Office Web Apps server named (OffWebApp)with the following commands and everything was up and running. Notice, you need to use the FQDN for the ServerName switch. See this TechNet article for more information.
New-SPWOPIBinding –ServerName offwebapp.powder.ski -AllowHTTP
Set-SPWopiZone –zone “internal-http”
Here’s a related blog post of mine about Office Web Apps Server installation errors that may also come in handy for you.