OEmbed LTI RCE Integration not working

[Velir]

I am trying to create an LTI RCE integration.

Followed this guide https://community.canvaslms.com/t5/The-Product-Blog/oEmbed-Token-Guide/ba-p/389707?search-action-id=...

I generate the return url similar to this :

https://myinstance.instructure.com/courses/149/external_content/success/external_tool_dialog?return_type=oembed&endpoint=https://mylocalserver/owh/canvas/OEMEmbed?url=http://google.com&width=600&height=600&url=http://google.com&oembed_token=token 

But it doesn't work Canvas is not hitting my `OEMEmbed ` url. Instead it just gets stuck with the following message Retrieving Content... and I can see the response of the get call is an empty object.

What could I be doing wrong?