Link showing "socialmeta.page.link" on Slack

Question

I'm generating a shortlink using the REST API. It works, but when I paste the link into Slack it shows "socialmeta.page.link" (see image) along with the metadata I've provided. Like this:

Here's the data I use to generate the link:

"dynamicLinkInfo": {
    "domainUriPrefix": "https://links.hearo.live",
    "link": document.location.origin + path,
    "androidInfo": {
        "androidPackageName": "live.hearo"
    },
    "iosInfo": {
        "iosBundleId": "live.hearo"
    },
    "socialMetaTagInfo": {
      "socialTitle": "Talk+Watch on Hearo.Live",
      "socialDescription": (username ? (username + " has invited you") : "You have been invited") + " to a Talk+Watch party on Hearo.Live",
      "socialImageLink": "https://a.hearo.live/hearo-images/hearo_logo_email.png"
    }
},

Am I doing something wrong?

Thanks.