I have a problem with SharePoint 2013 and Office Web Apps.
I have a SharePoint farm with two Web servers and two application servers, web servers and applications servers are on different network layers and in different subnets but no firewall between them.
I have a farm Office Web Apps with a single server that is configured with URL https internally and AlloHTTP False parameter has the certificate configured correctly.
In SharePoint I have configured a Web application with http URL an extension to https.
Communication between Office Web Apps and SharePoint 2013 goes through a load balancer and communication is correct but the request travels through https when it comes to SharePoint http returns.
I do not understand this behavior as SharePoint i am using the internal-https WopiZone and bindings are properly configured with the same
I understand that OWA will return http to render document (instead of defaut ) when user send https request to SharePoint library document.
Have you double-confirmed this behavior with Fiddler tool if OWA 2013 used http to render document?
Please use the below cmdle on OWA2013 server, make sure internal-https url is correct.
Please run the below cmdlet on SharePoint Server to verify internal-https is used for all office application extentions.
Get-SPWOPIZone | Get-SPWOPIBinding
Please run iisreset on Office Web App server (or reboot server if possible), see if it could help.
Also check if AAM is configured correctly for extended web application with https.
When I view https://sp/docC/11.xlsx in my envoronment, it returns https from OWA2013.
In this case confirm to the URL that displays Get-OfficeWebAppFarm is correct and which always used internal-https.
The configuration of the AAM is also correct, I have two zones, the Default and the Internet, the Default with HTTP and Internet with HTTPS.
Sorry for the late reply.
It seems OWA2013 will contact SharePoint default zone, please switch the Default and Internet zone URL setting, it means set the internet https url as default zone, then check results again.