WOPI Integration not displaying file content

Question

Hey,

We've implemented a WOPI protocol to integrate Microsoft Office into our React application. But we are falling short on one thing. We've successfully setup the server and endpoints for WOPI. We've handled the Auth using MSAL.

So in our WOPI server we're fetching the documents from Graph API's and returning the content, but the iframe handling the view only displays 'OK' string in it and nothing else. Any help would be appreciated.

Thanks