Android Question UltimateWebViewClient constant 404 error

the only way to prevent such an error is to provide the resource the webview is asking for. for example, if your local web page does not have a fav.ico, that would trigger an http 404 error, yet have nothing to do with a successful loading of the rest of your request. i assume your ultimatewebviewclient library makes a webchromeclient available. the log should confirm which resource is triggering the error. it isn't necessarily germane to compare android 5 vs android 6, or the particular versions of webview running on your devices. the only way to prevent an error message is to remove the error. error 404 refers to a missing resource. identify the resource and make it available. a missing fav.ico is typical.