30 sec preview url returning null

[axb1]

Plan

Free/Premium

Country

US

My Question or Issue

Hi I'm currently working on an Android app and I am utilizing Spotify's API. In my app I'm trying to fetch the 30 second preview urls for tracks. I recently noticed that not every track returns a 30 second preview url, some tracks return null. I found this odd, especially because if I copy and paste the Spotify link to a direct track and send it somewhere like Discord or Slack, the embed player allows you to play a 30 second preview of that track (whilst on the Spotify API this track returns as null). I guess my question is, is there any way to fetch an embed player's audio? Or is there any other way to grab the preview url of tracks? Is it possible to use an embed player on an Android app? I think there is definitely some 30 second preview URL for tracks, especially since an embed player can play them, I'm just confused on where else I could fetch them.

Thank you!