Unity 5.3 Editor is built with ATS enabled, which means all non-secured connection (HTTP) is not permitted. You will see an error message like this:
"The resource could not be loaded because the App Transport Security policy requires the use of a secure connection." and your page may stop loading.
We hope it is just a mistake and it could be turned off in later update. Currently, if you want to access HTTP content from UniWebView, you need to disable ATS manually in Unity's Info.plist file. Here is the steps for it:
- Open "/Applications/Unity/Unity.app/Contents/".
- Open "Info.plist" in this folder with a text editor.
- Add the entry below to just above the last
</dict>tag in the file, save it and restart your Unity.
Another possible issue is, in Unity 5.3, a new OpenGL Core is introduced for OS X editor in Unity to replace the original legacy OpenGL 2.1. You need to update to the latest version of UniWebView and it is compatible with the new OpenGL Core back-end.