Force inpage auth. iphone

With computer, ipad and every android, the authentication procedure is happening in screen. But with iPhone in standalone / app capable -mode it opens a new window in the safari browser.
This makes social login unusable for web apps, and we can’t have any of that, so I need a solution.
Is there a way to force the authentication to happen in “this” page?

— in this case —
In this spesific case we use a meta for standalone, and we prevent external links to open outside the app mode. The problem is only the redirect to the safari browser in auth. with FB on IPhone. Of course we use the WP social login plugin, and a self hosted wordpress (not the blog.wordpress.com).

— answer the noobs of coding —
I’ve seen this question in many different ways, concerning different social login plugins and with almost no good response. It’s beginning to irritate me. So if someone has a solution please share it with the rest of us, in a total basic way. What line, in which document should be replaced by what code. So that everyone can do it.

https://www.ads-software.com/plugins/wordpress-social-login/