ERR_UNKNOWN_URL_SCHEME
The ERR_UNKNOWN_URL_SCHEME error is commonly because of your browser issue . There's no application on your device which can handle that particular action. It is a Chromium bug . In Chrome version 40 and up, this bug has resurfaced, but only if you are manually entering the URL of the redirect page in the address bar. The issue is on the chromium issue tracker here .
This error sometimes gets triggered when you are trying to open another page of the interface . This error has one temporary solution. When the error gets encountered you need to backward and click to open the page again. Might this solution can temporarily move you away from this recent err_unknown_url_scheme on chrome and err_unknown_url_scheme on android.
You may get this "ERR_UNKNOWN_URL_SCHEME error" during mailto: or tel: links inside an iframe.
To solve it, try to add target="_blank" in your URL Scheme/Code.
For Example:
This error has no any specific solution till now. Android user and PC user all are facing this error which needs to be sought out. There's a long-standing bug in Chromium regarding how links without protocols are handled. It occasionally is patched, but seems to keep resurfacing. In some cases, prefixing your links with http:// (or https://) should resolve the issue for you:

What is URL Scheme
URL Scheme simply tells you how to interpret the part of the URL after the colon (:). The app: URL scheme can be used by packaged applications to obtain resources that are inside a container. These resources can then be used with web platform features that accept URLs. A URL Scheme is like "http://..." or "ftp://..." . At the simplest level, a custom URL scheme allows users to open your app from other apps. But the true power of URL schemes is in the ability to perform specific actions as your app opens. The scheme indicates the addressing system used. URL's are really a unification of various disparate addressing systems . The part before the colon identifies the scheme in use, and everything after the colon is syntax specific for the scheme. Each scheme defines its own unique way of addressing resources . This makes the URL standard infinitely extensible through adding new schemes.
It is hard to say anything in general for schemes , because they are wildly different. In many cases the name of the scheme is the name of a protocol which can be used to fetch the resource (like http, https, ftp etc.) but that is not hard rule, eg. the 'mailto' scheme indicates an e-mail address, but not a particular protocol. Some schemes does not correspond to any specific protocol, like the 'about' scheme used in web browsers, where the resource is not fetched via a protocol at all, but is built-in in the client.
NEXT.....Error on Port 443