A new patch is now pending review from Unity and should be released in a few days. The original version can trigger an exception if UnityCallFactory.GetVideoDevices() is called in WebGL if the project was build with Unity 2018.2 (and possibly other 2018 versions). The error is also triggered by the CallApp example.

You will get the following error message:
TypeError: Module.stringToUTF8 is not a function,TypeError: Module.stringToUTF8 is not a function

If you are using Unity 2018 with WebGL and don’t want to wait until the patch is released: You can open the file awrtc_unity.jslib and replace “Module.stringToUTF8” with “stringToUTF8”.

Update: The Asset has been updated and you will get the patched version automatically the next time you download & import the asset.