Failed to Load Resource, Plugin Handled Load on iOS

We were getting a similar error here. I thought it may have been the streaming issue since our video was hosted in blob storage on Azure. After setting up a Media Service for streaming, the video still didn't work. It turns out, the cause of the bug for us was Safari using a Service Worker. Below is some further explanation of what we found:

Safari first sends a byte range request for a Video tag that expects a 206 response. However, if you use a Service worker, the response returns with a 200 and it appears Safari doesn't know how to handle this. Our solution was to exclude using a Service Worker for Safari.

We found this by using the network tab of the Safari debugger on a Macbook to troubleshoot the issue we were seeing on the iPad. Attached is a screenshot for comparison/reference. The left tab shows what the call should look like by default. The right tab shows what you would see if using a Service Worker.

The solution to this problem was just a work around. The reason being the that blob servers aren't streaming servers. iOS devices expect the videos to arrive in small chunks. So for instance a streaming server is able to do this. However, a blob server just hands the video as a blob which is not what the iOS device expects. Some browsers are smart enough to handle this but others not.

The way I solved this was to add the video files outside of the blob server in a folder within the project and then render this through the Apache server instead of serving it via the actual blob server we were using. I hope this helps.