exec proxy not found for :: FabricPlugin :: addLog

[5Xtester]

When I try this for Browser platform,
window.fabric.Crashlytics.addLog("about to send a crash for testing!");
window.fabric.Crashlytics.sendCrash();

I get following error: exec proxy not found for :: FabricPlugin :: addLog and exec proxy not found for :: FabricPlugin :: sendCrash.
But I read that the error comes for Browser platform but works for Android or iOS builds, so I tried that, but there are no logs created using addLog method and sendCrash method also doesn't works.

the only crash logs I am getting are through the Fabric integration in XCode or Android Studio.

[uniphonic]

Errors won't report in the browser. It has to have the native code to work. Have you tried running it on a real device or simulator/emulator?

[5Xtester]

Its cordova app, and I have written the code in js file. Yes I tried running it on real simulator and device. Got same error. Will I have to write in native code and access from cordova and back, or something like that?