Issue with Rendering contentURL in invoking stageView of Teams Bot

I am currently facing an issue with rendering a contentURL in the modal view within the multistage view of my bot. I have implemented the following Adaptive Card, but the contentURL is not being rendered as expected. Instead, I’m getting the error message: “There was a problem reaching this app.” The same URL works correctly in a browser window.

Here is the sample Adaptive Card:

{
  "type": "Image",
  "url": "ImageURL",
  "altText": "Insights",
  "selectAction": {
    "type": "Action.Submit",
    "title": "Open",
    "data": {
      "msteams": {
        "type": "invoke",
        "value": {
          "type": "tab/tabInfoAction",
          "tabInfo": {
            "contentUrl": "https://apiserver.ngrok.app/test",
            "websiteUrl": "https://apiserver.ngrok.app/test",
            "name": "utterance",
            "entityId": "entityId",
            "openMode": "modal"
          }
        }
      }
    }
  }
}