Iframe error - {"message": "We\u2019re having a little trouble.", "title": "Sorry", "view": 7}

I'm using c# to upload videos using POST to Vimeo with a redirect URL to the same page (asp.net blazor wasm page). The upload aspect works great. The redirect from vimeo passes the video URI as query string (video_uri) which I use that url in an iframe to show the video.

However, when the redirect happens and I inject the video_uri query string var into the iframe, I get

{"message": "We\u2019re having a little trouble.", "title": "Sorry", "view": 7}

which is not helpful at all in terms of debugging. The iframe code was copied form the Vimeo site. If I wrap the iframe code with html and body tags and view it in the browser, it works as expected. The very same code doesn't work in the Blazor wasm app. Any suggestions?

The problem here is the src should be "https://player.vimeo.com/video/506803358" rather than "https://player.vimeo.com/videos/506803358". So 'video' not 'videos'.