Video IDs and thumbnails not working in iOS apps

I have a project with a lot of video links. I changed all of them to the new video ID system for the Android version of the app. It all works fine. Now I tested the same app for iOS in Simulator. The thumbnails are displayed but that’s it. I can’t get the videos to come up and play. I tried it with SAB 5.5 and 5.6. When I try the older version of the app (where the video links are directly added to the SFM files), the videos work.