Error Signing in to WhatsApp via WebView

Good afternoon people

I’m creating a WebView of a Site, so far so good, but on the site there is a button to open WhatsApp, if I enter through the Browser the What app I opened normal, more if I enter through the Error WebView, could someone help me?

WhatsApp detects that you are signing in from an app that doesn’t exist and that you built it yourself. WhatsApp also doesn’t want users making a copy of their official app for security reasons. However, you can change the user agent and make the WhatsApp Website think you are signing in form Google Chrome for example. It is not recommended as the user agent contains the browser version so after a long time WhatsApp will think you are using an older browser.

You can paste a chrome user agent here. Make sure to set the Android version you want for more accuracy.

Mozilla/5.0 (Linux; Android 10) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.185 Mobile Safari/537.36

For my problem, I found this solution from the image below, however and that it, as soon as the screen starts, it normally opens the WebView and opens the same page in the Browser, if I close the Browser and return to the WebView the button to call WhatsApp works normally.